2,477 results on '"*SHUBNIKOV-de Haas effect"'
Search Results
2. Thermoelectric Figure of Merit and Quantum Mobility of Holes in Copper-Doped Antimony-Telluride Single Crystals.
- Author
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Kul'bachinskii, V. A., Kytin, V. G., Apreleva, A. S., and Konstantinova, E. A.
- Subjects
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SINGLE crystals , *HOLE mobility , *ELECTRON paramagnetic resonance , *THERMOELECTRIC materials , *COPPER crystals , *SEEBECK coefficient , *ANTIMONY , *ELECTRON paramagnetic resonance spectroscopy - Abstract
The thermoelectric properties of Sb2 – xCuxTe3 single crystals (0 ≤ x ≤ 0.10) synthesized by the Bridgman method are studied in the temperature range of 77 K < T < 350 K. It turns out that the hole concentration and electrical conductivity strongly increase, while the Seebeck coefficient slightly decreases when Sb2Te3 crystals are doped with copper. The thermal conductivity of crystals doped with copper is somewhat higher than that of the initial Sb2Te3 crystals. As a result, the thermoelectric figure of merit ZT increases with increasing copper content at T > 300 K. In addition, the quantum mobility of holes μq in Sb2 – xCuxTe3 (0 ≤ x ≤ 0.10), Sb2 – xSnxTe3 (0 ≤ x ≤ 0.01), and Sb2 – xTlxTe3 (0 ≤ x ≤ 0.05) single crystals is measured using data on the Shubnikov–de Haas (SdH) effect. Electron paramagnetic resonance (EPR) measurements show that copper ions in the studied samples are most likely in the spinless Cu+1 state. [ABSTRACT FROM AUTHOR] more...
- Published
- 2022
- Full Text
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3. Effects of GaN interlayer on the transport properties of lattice-matched AlInN/AlN/GaN heterostructures.
- Author
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Wu, F., Gao, K. H., Li, Z. Q., Lin, T., and Zhou, W. Z.
- Subjects
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ALUMINUM indium nitride , *ALUMINUM nitride , *GALLIUM nitride , *ELECTRICAL properties of electron gas , *HALL mobility , *SHUBNIKOV-de Haas effect , *INTERFACIAL roughness , *HETEROSTRUCTURES - Abstract
We study the effects of GaN interlayer on the transport properties of two-dimensional electron gases confined in lattice-matched AlInN/AlN/GaN heterostructures. It is found that the Hall mobility is evidently enhanced when an additional ultrathin GaN interlayer is introduced between AlInN and AlN layers. The enhancement of the Hall mobility is especially remarkable at low temperature. The high Hall mobility results in a low sheet resistance of 23Ω=⧠ at 2K. Meanwhile, Shubnikov-de Haas oscillations (SdH) are also remarkably enhanced due to the existence of GaN interlayer. The enhancement of the SdH oscillations is related to the larger quantum mobility μq owing to the suppression of the interface roughness, alloy disorder, and ionized impurity scatterings by the GaN interlayer. [ABSTRACT FROM AUTHOR] more...
- Published
- 2015
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4. Correlation Between Bands Structure and Quantum Magneto Transport Properties in InAs/GaxIn1−xSb Type II Superlattice for Infrared Detection
- Author
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Nassima Benchtaber, Abdelhakim Nafidi, Driss Barkissy, Abderrezak Boutramine, Merieme Benaadad, Samir Melkoud, Es-Said Es-Salhi, and Fatiha Chibane
- Subjects
bands structure ,quantum magneto transport ,Shubnikov-de Haas effect ,density of states ,InAs/GaxIn1-xSb superlattice ,infrared detection ,Physics ,QC1-999 - Abstract
We have used the envelope function formalism to investigate the bands structure of LWIR type II SL InAs (d1 = 2. 18d2)/In0.25Ga0.75Sb(d2 = 21.5 Å). Thus, we extracted optical and transport parameters as the band gap, cut off wavelength, carriers effective mass, Fermi level and the density of state. Our results show that the higher optical cut-off wavelength can be achieved with smaller layer thicknesses. The semiconductor-semi metal transition was studied as a function of temperature. Our results permit us the interpretations of Hall and Shubnikov-de Haas effects. These results are in agreement with experimental results in literature and a guide for engineering infrared detectors. more...
- Published
- 2020
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5. Evidence for topological semimetallicity in a chain-compound TaSe3.
- Author
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Saleheen, Ahmad Ikhwan Us, Chapai, Ramakanta, Xing, Lingyi, Nepal, Roshan, Gong, Dongliang, Gui, Xin, Xie, Weiwei, Young, David P., Plummer, E. W., and Jin, Rongying
- Subjects
SINGLE crystals ,MAGNETORESISTANCE ,MAGNETIC fields ,ELECTRICAL resistivity ,SHUBNIKOV-de Haas effect - Abstract
Among one-dimensional transition-metal trichalcogenides, TaSe
3 is unconventional in many respects. One is its strong topological semimetallicity as predicted by first-principles calculations. We report the experimental investigations of the electronic properties of one-dimensional-like TaSe3 single crystals. While the b-axis electrical resistivity shows good metallicity with a high residual resistivity ratio greater than 100, an extremely large magnetoresistance is observed reaching ≈7 × 103 % at 1.9 K for 14 T. Interestingly, the magnetoresistance follows the Kohler's rule with nearly quadratic magnetic field dependence, consistent with the electron–hole compensation scenario as confirmed by our Hall conductivity data. Both the longitudinal and Hall conductivities show Shubnikov-de Haas oscillations with two frequencies: Fα ≈ 97 T and Fβ ≈ 186 T. Quantitative analysis indicates that Fα results from the two-dimensional-like electron band with the non-trivial Berry phase [1.1π], and Fβ from the hole band with the trivial Berry phase [0(3D) − 0.16π(2D)]. Our experimental findings are consistent with the predictions based on first-principles calculations. [ABSTRACT FROM AUTHOR] more...- Published
- 2020
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6. Superconductivity and Shubnikov - de Haas effect in polycrystalline Cd3As2 thin films.
- Author
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Oveshnikov, Leonid N., Davydov, Alexander B., Suslov, Alexey V., Ril', Alexey I., Marenkin, Sergey F., Vasiliev, Alexander L., and Aronzon, Boris A.
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CADMIUM compounds , *POLYCRYSTALS , *SUPERCONDUCTIVITY , *SHUBNIKOV-de Haas effect , *THIN films - Abstract
In this study we observed the reproducible superconducting state in Cd3As2 thin films without any external stimuli. Comparison with our previous results reveals similar qualitative behavior for films synthesized by different methods, while the difference in the values of the critical parameters clearly shows the possibility to control this state. The X-ray diffraction measurements demonstrate the presence of the tetragonal Cd3As2 crystal phase in studied films. Measurements of high-field magnetoresistance reveal pronounced Shubnikov - de Haas oscillations. The analysis of these oscillations suggests that, due to high carrier concentration in studied Cd3As2 films, the initial Dirac semimetal phase may be partially suppressed, which, however, does not contradict with possible topological nature of the observed superconductivity. [ABSTRACT FROM AUTHOR] more...
- Published
- 2020
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7. Transverse Shubnikov–de Haas effect and the manifestation of quantum diffraction.
- Author
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Berezhnoy, Yu. A. and Molev, A. S.
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ELECTRIC conductivity , *TRANSITION metals , *ELECTRON transitions , *DIFFRACTION patterns - Abstract
A quantum diffraction interpretation of the transverse Shubnikov–de Haas effect is presented. Within the framework of the conventional theory of this effect, we show that the matrix element for the electron transition from an initial state to a final state used in calculating the transverse electrical conductivity can be represented as a diffraction-type amplitude distribution. The squared modulus of this matrix element under certain conditions exhibits the Fraunhofer diffraction pattern. It is shown that the oscillating part of the transverse conductivity has the same form as the amplitude for Fraunhofer diffraction by an annular aperture. [ABSTRACT FROM AUTHOR] more...
- Published
- 2020
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8. Aperiodic quantum oscillations in the two-dimensional electron gas at the LaAlO3/SrTiO3 interface.
- Author
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Rubi, Km, Gosteau, Julien, Serra, Raphaël, Han, Kun, Zeng, Shengwei, Huang, Zhen, Warot-Fonrose, Benedicte, Arras, Rémi, Snoeck, Etienne, Ariando, Goiran, Michel, and Escoffier, Walter
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ELECTRON gas ,APERIODICITY ,MAGNETIC field effects ,SHUBNIKOV-de Haas effect ,DENSITY functional theory ,ELECTRONIC band structure - Abstract
Despite several attempts, the intimate electronic structure of two-dimensional electron systems buried at the interface between LaAlO
3 and SrTiO3 still remains to be experimentally revealed. Here, we investigate the transport properties of a high-mobility quasi-two-dimensional electron gas at this interface under high magnetic field (55 T) and provide new insights for electronic band structure by analyzing the Shubnikov-de Haas oscillations. Interestingly, the quantum oscillations are not 1∕B-periodic and produce a highly non-linear Landau plot (Landau level index versus 1/B). We explore different scenarios leading to 1/B-aperiodic oscillations where the charge and the chemical potential vary as the magnetic field increases. Overall, the magneto-transport data are discussed in light of high-resolution scanning transmission electron microscopy (HRSTEM) analysis of the interface as well as calculations from density functional theory. [ABSTRACT FROM AUTHOR] more...- Published
- 2020
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9. Effective mass of two-dimensional electrons in InGaAsN/GaAsSb type II quantum well by Shubnikov-de Haas oscillations.
- Author
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Shuichi Kawamata, Akira Hibino, Sho Tanaka, and Yuichi Kawamura
- Subjects
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QUANTUM wells , *INDIUM gallium arsenide nitride , *ANTIMONY compounds , *EFFECTIVE mass (Physics) , *SHUBNIKOV-de Haas effect - Abstract
In order to develop optical devices for 2-3 µm wavelength regions, the InP-based InGaAs/GaAsSb type II multiple quantum well system has been investigated. By doping nitrogen into InGaAs layers, the system becomes effective in creating the optical devices with a longer wavelength. In this report, electrical transport properties are reported on the InGaAsN/GaAsSb type II system. The epitaxial layers with the single hetero or multiple quantum well structure on InP substrates are grown by the molecular beam epitaxy. The electrical resistance of samples with different nitrogen concentrations has been measured as a function of the magnetic field up to 9 Tesla at several temperatures between 2 and 6K. The oscillation of the resistance due to the Shubnikov-de Haas (SdH) effect has been observed at each temperature. The effective mass is obtained from the temperature dependence of the amplitude of the SdH oscillations. The value of the effective mass increases from 0.048 for N=0.0% to 0.062 for N=1.2 and 1.5% as the nitrogen concentration increases. The mass enhancement occurs with corresponding to the reduction of the bandgap energy. These results are consistent with the band anticrossing model. [ABSTRACT FROM AUTHOR] more...
- Published
- 2016
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10. Magnetotransport in BEDT-TTF salts
- Author
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Nam, Moon-Sun
- Subjects
530.41 ,BEDT-TTF ,MAGNETIC FIELDS ,MAGNETORESISTANCE ,ANGULAR DISTRIBUTION ,COMPUTERIZED SIMULATION ,FERMI LEVEL ,TEMPERATURE DEPENDENCE ,SHUBNIKOV-DE HAAS EFFECT - Published
- 2000
11. Thermoelectric Figure of Merit and Quantum Mobility of Holes in Copper-Doped Antimony-Telluride Single Crystals
- Author
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Kul’bachinskii, V. A., Kytin, V. G., Apreleva, A. S., and Konstantinova, E. A.
- Published
- 2022
- Full Text
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12. High magnetic field studies of BEDT-TTF organic conductors
- Author
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Honold, Markus Michael
- Subjects
530.41 ,BEDT-TTF ,THIOCYANATES ,MERCURY COMPOUNDS ,MAGNETIC FIELDS ,MAGNETIC PROPERTIES ,ELECTRIC CONDUCTORS ,SHUBNIKOV-DE HAAS EFFECT ,TEMPERATURE DEPENDENCE ,MAGNETORESISTANCE - Published
- 1999
13. Electrical properties of Si/Siâ†1â†-â†xGeâ†x/Si inverted modulation doped structures
- Author
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Sadeghzadeh, Mohammad Ali
- Subjects
541 ,MOLECULAR BEAM EPITAXY ,INTERFACES ,SILICON ,GERMANIUM SILICIDES ,LAYERS ,HALL EFFECT ,MAGNETORESISTANCE ,TEMPERATURE DEPENDENCE ,ELECTRIC CONDUCTIVITY ,SHUBNIKOV-DE HAAS EFFECT - Published
- 1998
14. Quantum effects in a germanium quantum well with ultrahigh mobility of charge carrier.
- Author
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Berkutov, I. B., Andrievskii, V. V., Kolesnichenko, Yu. A., and Mironov, O. A.
- Subjects
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CHARGE carrier mobility , *HALL effect , *FERMI liquids , *ELECTRON-electron interactions , *GERMANIUM , *COUPLING constants , *QUANTUM wells , *QUANTUM interference - Abstract
Quantum effects in p-type Si0.2Ge0.8/Ge/Si0.2Ge0.8 heterostructure with an extremely high mobility of charge carriers μH = 1367000 cm2/(V ⋅ s) have been comprehensively studied. An analysis of Shubnikov–de Haas oscillations yielded effective mass of charge carriers, which proved to be very low, m* = 0.062m0, and the value of fluctuations of hole density along the channel δp = 3.5 ⋅ 109 cm–2. The fractional Hall effect (filling numbers 8/3, 7/3, 5/3, 4/3) observed at temperatures up to 5 K has been discovered in strong magnetic fields. The studies of quantum interference effects related to weak localization and electron-electron interaction between charge carriers, which have been conducted in such a high-mobility system for the first time, enabled calculation of spin splitting Δ = 1.07 meV and the Fermi-liquid coupling constant F 0 σ = − 0.12 , which agree with results obtained earlier. [ABSTRACT FROM AUTHOR] more...
- Published
- 2019
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15. Investigations in electronic quantum transport of quasi two dimensional InxGa1-xAs/InP nanostructure superlattice for infrared detection.
- Author
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Barkissy, D., Nafidi, A., Boutramine, A., El Yakoubi, E.Y., and Chaib, H.
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NANOSTRUCTURED materials , *SUPERLATTICES , *INFRARED detectors , *QUANTUM transitions , *THICKNESS measurement - Abstract
Abstract We investigated, theoretically, the electronic band structures, transport and magneto-transport properties of In 0.53 Ga 0.47 As(d 1 = 10 nm)/InP(d 2 = 5 nm) lattice matched superlattice (SL) at 1.7 K. These studies were performed in the envelope function formalism with effects of well thickness d 1. The SL has a direct band gap of 849 meV and the cut-off wavelength of 1.46 μm indicates that it can be used as a short infrared detector. The computed density of states and position of Fermi level, predict that this sample is a quasi two-dimensional system and exhibits n type conductivity. We have interpreted the oscillations in the magneto-resistance observed by Pusep et al. in this superlattice. These results were compared and discussed with the available data in the literature. Highlights • Mini-bands width decrease to discrete levels of a multi-quantum well as d 1 increases. • Density of states is quantized in term of m∗/πℏ2d. • Dispersion curves indicate a quasi two dimensional system. • Position of Fermi level, predict n type conductivity in the investigated sample. • Quantization of mini-bands into Landau mini-bands demonstrates the presence of SdH and QHE. [ABSTRACT FROM AUTHOR] more...
- Published
- 2019
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16. Studies on Shubnikov-de Haas oscillations and magnetic properties of cobalt-doped Bi1.9Co0.05 Sb0.05Se3 topological single crystals.
- Author
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Amaladass, E.P., Satya, A.T., Sharma, Shilpam, Vinod, K., and Mani, Awadhesh
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BISMUTH alloys , *SHUBNIKOV-de Haas effect , *COBALT , *DOPED semiconductors , *TOPOLOGY , *SINGLE crystals , *MAGNETIC properties of metals - Abstract
Abstract Magnetotransport and magnetic properties of pristine Bi 1.9 Sb 0.1 Se 3 (BSS) and Co-doped Bi 1.9 Co 0.05 Sb 0.05 Se 3 (BCSS) topological insulator (TI) single crystals are reported. Both the samples show metallic behavior, but the overall resistivity decreases upon Co doping. Temperature and field dependent magnetization, M (H) and M (T) measurements on BSS exhibit diamagnetic nature from 2.8 K to 300 K. Whereas at T ≤ 10 K, Co-doped sample shows a paramagnetic behavior in low field range and a diamagnetic behavior at H ≥ ±3.5 T. The analysis of M (H) and M (T) data reveals that Co2+ and Co3+ might coexist in the diamagnetic matrix. Hall measurements indicate that the carriers are n-type and its density increases by one order of magnitude upon Cobalt doping. The Hall mobility decreases in BCSS, and its temperature dependence shows an increasing behavior as the temperature decreases in both the samples. The Shubnikov-de Haas (SdH) oscillations have been analyzed using Lifshitz-Kosovich (LK) equation. The frequency of SdH oscillation drastically increases for BCSS pointing to the fact that the Fermi energy (E F) is shifted upward and the mobility of surface state electrons decreases. The substituted Co atoms act as paramagnetic entities and are found to be strong electron donors as well as strong scattering centers. The Berry curvature β derived from LK fit increases from 0.56 to 0.8 upon Co doping and shows the contribution of non-Dirac like bands to the SdH oscillations. Graphical abstract Image 1 Highlights • Magnetic and transport properties of Bi 1.9 Co 0.05 Sb 0.05 Se 3 (BCSS) are reported. • Co dopants behave as paramagnetic entities in a diamagnetic matrix. • The frequency of Shubnikov-de Haas oscillations increases. • The surface mean free path (ls), mobility (μ), and scattering time (τ) decreases. • The contribution from non-Dirac fermions in the electronic transport is evident. [ABSTRACT FROM AUTHOR] more...
- Published
- 2019
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17. The electron structure of Pb1–x–ySnxFeyTe alloys.
- Author
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Skipetrov, E. P., Kovalev, B. B., Skipetrova, L. A., Knotko, A. V., and Slynko, V. E.
- Subjects
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TELLURIUM alloys , *LEAD tin telluride crystals , *ELECTRONIC band structure , *METAL inclusions , *GALVANOMAGNETIC effects , *SHUBNIKOV-de Haas effect , *FERMI energy , *VALENCE bands - Abstract
A study of phase and elemental compositions, galvanomagnetic properties (4.2 K ≤ T ≤ 300 K, B ≤ 0.07 T) and Shubnikov – de Haas oscillations (T = 4.2 K, B ≤ 6.5 T) in Pb1–x–ySnxFeyTe alloys with varying concentrations of tin and iron in single-crystal ingots synthesized using the Bridgman-Stockbarger method was performed. Scanning electron microscopy and X-ray fluorescence microanalysis revealed the presence of iron enriched microscopic inclusions, and the distribution of tin and iron along the ingots was determined. An increase in the concentration of holes with increasing concentrations of tin and iron, as well as anomalous temperature dependences of the Hall coefficient, which indicates a pinning of the Fermi level at the resonant level of iron, were detected. A model of electron structure rearrangement is proposed in order to explain the experimental dependences of the hole concentration and the Fermi energy relative to the valence band top as a function of tin concentration in the alloys. The model assumes that the iron level moves from the top to the depth of the valence band as the tin concentration increases. The compositional coefficient of iron level movement relative to the edges of the energy bands with increasing tin content in Pb1–x–ySnxFeyTe alloys is determined using the two-band Kane dispersion law. [ABSTRACT FROM AUTHOR] more...
- Published
- 2019
- Full Text
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18. Spin splitting of surface states in HgTe quantum wells.
- Author
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Dobretsova, A. A., Kvon, Z. D., Krishtopenko, S. S., Mikhailov, N. N., and Dvoretsky, S. A.
- Subjects
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MERCURY telluride , *QUANTUM wells , *SURFACE states , *SHUBNIKOV-de Haas effect , *CONDUCTION bands , *QUANTUM spin models , *ELECTROSTATICS , *FERMI level - Abstract
We report on beating appearance in Shubnikov-de Haas oscillations in conduction band of 18–22 nm HgTe quantum wells under applied top-gate voltage. Analysis of the beatings reveals two electron concentrations at the Fermi level arising due to Rashba-like spin splitting of the first conduction subband H1. The difference ΔNs in two concentrations as a function of the gate voltage is qualitatively explained by a proposed toy electrostatic model involving the surface states localized at quantum well interfaces. Experimental values of ΔNs are also in a good quantitative agreement with self-consistent calculations of Poisson and Schrödinger equations with eight- band k ⋅ p Hamiltonian. Our results clearly demonstrate that the large spin splitting of the first conduction subband is caused by surface nature of H1 states hybridized with the heavy-hole band. [ABSTRACT FROM AUTHOR] more...
- Published
- 2019
- Full Text
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19. Shubnikov–de Haas Oscillations in Semiconductors at the Microwave-Radiation Absorption.
- Author
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Gulyamov, G., Erkaboev, U. I., and Gulyamov, A. G.
- Subjects
SHUBNIKOV-de Haas effect ,SEMICONDUCTORS ,MAGNETO-absorption ,MATHEMATICAL models ,TEMPERATURE effect - Abstract
Mathematical models for the Shubnikov-de Haas oscillations in semiconductors are obtained at the microwave-radiation absorption and its temperature dependence. Three-dimensional image of microwave magnetoabsorption oscillations in narrow-gap semiconductors is established. Using a mathematical model, the oscillations of the microwave magnetoabsorption are considered for different values of the electromagnetic field. The results of calculations are compared with experimental data. The proposed model explains the experimental results in HgSe at different temperatures. [ABSTRACT FROM AUTHOR] more...
- Published
- 2019
- Full Text
- View/download PDF
20. Determination of g-factor in a quantum well channel with a strong Rashba effect.
- Author
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Won Young Choi, Joonyeon Chang, Jung Hoon Lee, and Hyun Cheol Koo
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QUANTUM wells , *MAGNETIC fields , *SHUBNIKOV-de Haas effect , *MAGNETORESISTANCE , *RASHBA effect - Abstract
Using the Shubnikov-de Haas oscillation measurement, the g-factor of carriers in a strong Rashba system is observed. To determine g-factor of carriers in the InAs quantum well channel with a strong Rashba effect, the magnetic fields are simultaneously applied along the in-plane direction and the perpendicular direction. The perpendicular field drives the oscillation of conductance for measuring Rashba spin orbit interaction and the in-plane field parallel to the Rashba field interacts with Rashba effect and modifies the intrinsic Rashba parameter. The total field inside the channel is a combination of the Rashba field and the in-plane field, so the modification of Rashba parameter gives a g-factor value of ~13 in our system. [ABSTRACT FROM AUTHOR] more...
- Published
- 2014
- Full Text
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21. Two-Dimensional Surface Topological Nanolayers and Dirac Fermions in Single Crystals of the Diluted Magnetic Semiconductor (Cd1−x−yZnxMny)3As2 (x + y = 0.3)
- Author
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Vasilii Zakhvalinskii, Tatyana Nikulicheva, Evgeny Pilyuk, Oleg Ivanov, Aleksey Kochura, Alexander Kuzmenko, Erkki Lähderanta, and Alexander Morocho
- Subjects
diluted magnetic semiconductor ,Shubnikov–de Haas effect ,cadmium arsenide ,three-dimensional topological Dirac semimetals ,2D topological nanolayers ,Crystallography ,QD901-999 - Abstract
Features in the transverse magnetoresistance of single-crystalline diluted magnetic semiconductors of a (Cd1−x−yZnxMny)3As2 system with x + y = 0.3 have been found and analyzed in detail. Two groups of samples have been examined. The samples of the first group were thermally annealed for a long time, whereas the samples of the second group were not thermally annealed. The Shubnikov–de Haas (SdH) oscillations were observed for both groups of the samples within a 4.2 ÷ 30 K temperature range and under transverse magnetic field sweeping from 0 up to 11 T. The value of a phase shift, according to the SdH oscillations, was found to be a characteristic of the Berry phase existing in all the samples, except the unannealed sample with y = 0.08. Thickness of 2D surface topological nanolayers for all the samples was estimated. The thickness substantially depended on Mn concentration. The experimental dependence of reduced cyclotron mass on the Fermi wave vector, extracted from the SdH oscillations for the samples with different doping levels, is in satisfactory agreement with the predicted theoretical linear dependence. The existence of the Dirac fermions in all the samples studied (except the unannealed sample with y = 0.08) can be concluded from this result. more...
- Published
- 2020
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22. Transport evidence of mass-less Dirac fermions in (Cd1−x−yZnxMny)3As2 (x + y = 0.4)
- Author
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V S Zakhvalinskii, T B Nikulicheva, E A Pilyuk, E Lähderanta, M A Shakhov, O N Ivanov, E P Kochura, A V Kochura, and B A Aronzon
- Subjects
Shubnikov–de Haas effect ,mass-less Dirac fermions ,3D topological Dirac semimetals ,diluted magnetic semiconductor ,Materials of engineering and construction. Mechanics of materials ,TA401-492 ,Chemical technology ,TP1-1185 - Abstract
Charge carriers parameters on a 2D-layer surface for (Cd _1−x−y Zn _x Mn _y ) _3 As _2 ( y = 0.08) (the concentration ${n}_{2D}$ = 1.9 × 10 ^12 cm ^–2 , the effective value of the 2D-layer ${d}_{2D}={n}_{2D}/{n}_{3D}$ = 14.5 nm, the wave vector ${k}_{F}$ = 0.1 nm ^–1 , the charge carriers relaxation time due to dispersion ${\tau }_{D}$ = 1.8 × 10 ^–13 s, the velocity of charge carriers on Fermi surface ${v}_{F}=\hslash {k}_{F}/{m}_{c}$ = 2.6 ^5 × 10 ^5 m s ^−1 , the mean free path ${l}_{F}={v}_{F}{\tau }_{D}$ = 47.7 nm) were determined. It was found that the dependence of the cyclotron m ass m _с (0)/m _0 on Fermi wave vector k _F for (Cd _1−x−y Zn _x Mn _y ) _3 As _2 ( y = 0.08) is in compliance with a theoretical linear dependence, that describes mass-less Dirac fermions. more...
- Published
- 2020
- Full Text
- View/download PDF
23. Galvano- and thermo-magnetic effects at low and high temperatures within non-Markovian quantum Langevin approach.
- Author
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Abdurakhmanov, I.B., Adamian, G.G., Antonenko, N.V., and Kanokov, Z.
- Subjects
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LANGEVIN equations , *STOCHASTIC differential equations , *QUANTUM theory , *CHARGE carriers , *EXCITON-phonon interactions - Abstract
The quantum Langevin formalism is used to study the charge carrier transport in a two-dimensional sample. The center of mass of charge carriers is visualized as a quantum particle, while an environment acts as a heat bath coupled to it through the particle–phonon interaction. The dynamics of the charge carriers is limited by the average collision time which takes effectively into account the two-body effects. The functional dependencies of particle–phonon interaction and average collision time on the temperature and magnetic field are phenomenologically treated. The galvano-magnetic and thermo-magnetic effects in the quantum system appear as the results of the transitional processes at low temperatures. [ABSTRACT FROM AUTHOR] more...
- Published
- 2018
- Full Text
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24. Heterogeneous integration of InAs/GaSb tunnel diode structure on silicon using 200 nm GaAsSb dislocation filtering buffer.
- Author
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Liu, J.-S., Clavel, M., Pandey, R., Datta, S., Xie, Y., Heremans, J. J., and Hudait, M. K.
- Subjects
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INDIUM arsenide , *GALLIUM antimonide , *SHUBNIKOV-de Haas effect - Abstract
An InAs/GaSb tunnel diode structure was heterogeneously integrated on silicon by solid source molecular beam epitaxy using a 200 nm strained GaAs1-ySby dislocation filtering buffer. X-ray analysis demonstrated near complete strain relaxation of the metamorphic buffer and a quasi-lattice-matched InAs/GaSb heterostructure, while high-resolution transmission electron microscopy revealed sharp, atomically abrupt heterointerfaces between the GaSb and InAs epilayers. In-plane magnetotransport analysis revealed Shubnikov-de Haas oscillations, indicating the presence of a dominant high mobility carrier, thereby testifying to the quality of the heterostructure and interfaces. Temperature-dependent current-voltage characteristics of fabricated InAs/GaSb tunnel diodes demonstrated Shockley-Read-Hall generation-recombination at low bias and band-to-band tunneling transport at high bias. The extracted conductance slope from the fabricated tunnel diodes increased with increasing temperature due to thermal emission (Ea ∼ 0.48 eV) and trap-assisted tunneling. Thus, this work illustrates the significance of defect control in the heterointegration of metamorphic InAs/GaSb tunnel diode heterostructures on silicon when using GaAs1-ySby dislocation filtering buffers. [ABSTRACT FROM AUTHOR] more...
- Published
- 2018
- Full Text
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25. Deviation from the Kohler's rule and Shubnikov–de Haas oscillations in type-II Weyl semimetal WTe2: High magnetic field study up to 56 T.
- Author
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Onishi, Shota, Jha, Rajveer, Miyake, Atsushi, Higashinaka, Ryuji, Matsuda, Tatsuma D., Tokunaga, Masashi, and Aoki, Yuji
- Subjects
- *
SHUBNIKOV-de Haas effect , *MAGNETORESISTANCE , *SINGLE crystals - Abstract
We have measured magnetoresistance of type-II Weyl semimetal WTe2 in high magnetic fields of B//c up to B = 56 T using a high quality single crystal with the residual resistivity ratio 1330. A Kohler plot demonstrates the existence of a deviation from the B2 dependence. Significant deviation from Kohler's rule appears with increasing temperature, indicating wave-vector k dependent anisotropic carrier scattering, which develops with increasing temperature. The fast-Fourier-transform spectra of the observed large-amplitude Shubnikov–de Haas oscillations confirm the existence of four fundamental and one additional (cyclotron frequency of 255 T) peaks. The amplitude of the latter one increases anomalously with increasing field, confirming this oscillation being due to magnetic breakdown (or magnetic breakthrough) between the two cyclotron orbits of the adjacent hole pockets. [ABSTRACT FROM AUTHOR] more...
- Published
- 2018
- Full Text
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26. Shubnikov–de Haas Oscillations in the Magnetoresistance of Layered Conductors in Proximity to the Topological Lifshitz Transition.
- Author
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Peschansky, V. G., Kartsovnik, M. V., and Fust, S.
- Subjects
- *
SHUBNIKOV-de Haas effect , *OSCILLATIONS , *MAGNETORESISTANCE , *TOPOLOGICAL algebras , *LIFSHITZ point (Physics) , *PHASE transitions - Abstract
The dependence of the resistance of a layered conductor with a quasi-two-dimensional charge carrier energy spectrum on the strength and orientation of a quantizing magnetic field is studied. The case of an organic conductor with a multisheet Fermi surface consisting of a weakly warped cylinder and two adjoining planar sheets is considered. By applying an external pressure to the conductor or doping it with impurity atoms, the gap between the cylinder and the planar sheets of the Fermi surface (FS) may be reduced so that electrons start wandering on the FS, tunneling between its different parts due to magnetic breakdown. If an electron can pass through all the different sheets of the FS several times during the mean free time, its motion in the plane orthogonal to the magnetic field becomes finite. This leads to Shubnikov–de Haas oscillations with a period determined by the area enclosed by the closed breakdown orbit of an electron in momentum space. However, even at a slight tilting of the field from the normal to the layers by an angle ϑ, the equidistance is broken and at certain angles ϑk the probability of the magnetic breakdown to one of the planar FS sheets may become so low that the electron cannot complete the magnetic-breakdown orbit and its motion over the other planar sheet and the cylindrical part of the FS becomes infinite. As a result, magnetic-breakdown quantum oscillations of magnetization and all kinetic properties vanish. This vanishing repeats periodically as a function of tan ϑ with changing the tilt angle. Possibilities for experimental observation and investigation of the influence of magnetic breakdown on quantum oscillation phenomena are discussed. [ABSTRACT FROM AUTHOR] more...
- Published
- 2018
- Full Text
- View/download PDF
27. Extreme magnetoresistance and Shubnikov-de Haas oscillations in ferromagnetic DySb.
- Author
-
Liang, D. D., Wang, Y. J., Xi, C. Y., Zhen, W. L., Yang, J., Pi, L., Zhu, W. K., and Zhang, C. J.
- Subjects
SHUBNIKOV-de Haas effect ,MAGNETORESISTANCE ,FERROMAGNETIC materials - Abstract
The electronic structures of a representative rare earth monopnictide (i.e., DySb) under high magnetic field (i.e., in the ferromagnetic state) are studied from both experimental and theoretical aspects. A non-saturated extremely large positive magnetoresistance (XMR) is observed (as large as 3.7 × 10
4 % at 1.8 K and 38.7 T), along with the Shubnikov-de Haas oscillations that are well reproduced by our first principles calculations. Three possible origins of XMR are examined. Although a band inversion is found theoretically, suggesting that DySb might be topologically nontrivial, it is deeply underneath the Fermi level, which rules out a topological nature of the XMR. The total densities of electron-like and hole-like carriers are not fully compensated, showing that compensation is unlikely to account for the XMR. The XMR is eventually understood in terms of high mobility that is associated with the steep linear bands. This discovery is important to the intensive studies on the XMR of rare earth monopnictides. [ABSTRACT FROM AUTHOR] more...- Published
- 2018
- Full Text
- View/download PDF
28. Oscillating planar Hall response in bulk crystal of topological insulator Sn doped Bi1.1Sb0.9Te2S.
- Author
-
Wu, Bin, Pan, Xing-Chen, Wu, Wenkai, Fei, Fucong, Chen, Bo, Liu, Qianqian, Bu, Haijun, Cao, Lu, Song, Fengqi, and Wang, Baigeng
- Subjects
- *
SURFACE states , *SHUBNIKOV-de Haas effect , *SINGLE crystals , *MAGNETIC fields , *HALL effect - Abstract
We report the low-temperature magneto-transport in the bulk-insulating single crystal of topological insulator Sn doped Bi1.1Sb0.9Te2S. Shubnikov-de Haas oscillations appear with their reciprocal frequency proportional to cos θ , demonstrating the dominant transport of topological surface states. While the magnetic field rotates on the sample surface, the planar Hall effect arises with sizeable oscillations following a relation of cos θ sin θ. Its amplitude reaches the maximum at the lowest temperature and drops to nearly zero at temperature higher than 100 K. All these evidences consolidate such planar Hall oscillations as another golden criterion on the topological surface transport. [ABSTRACT FROM AUTHOR] more...
- Published
- 2018
- Full Text
- View/download PDF
29. Transport properties of Cu-doped bismuth selenide single crystals at high magnetic fields up to 60 Tesla: Shubnikov–de Haas oscillations and [formula omitted]-Berry phase.
- Author
-
Romanova, Taisiia A., Knyazev, Dmitry A., Wang, Zhaosheng, Sadakov, Andrey V., and Prudkoglyad, Valery A.
- Subjects
- *
BISMUTH selenide , *COPPER , *SINGLE crystals , *MAGNETIC fields , *SHUBNIKOV-de Haas effect , *GEOMETRIC quantum phases - Abstract
We report Shubnikov-de Haas (SdH) and Hall oscillations in Cu-doped high quality bismuth selenide single crystals. To increase the accuracy of Berry phase determination by means of the of the SdH oscillations phase analysis we present a study of n-type samples with bulk carrier density n ∼ 10 19 − 10 20 cm − 3 at high magnetic field up to 60 Tesla. In particular, Landau level fan diagram starting from the value of the Landau index N = 4 was plotted. Thus, from our data we found π -Berry phase that directly indicates the Dirac nature of the carriers in three-dimensional topological insulator (3D TI) based on Cu-doped bismuth selenide. We argued that in our samples the magnetotransport is determined by a general group of carriers that exhibit quasi-two-dimensional (2D) behaviour and are characterized by topological π -Berry phase. Along with the main contribution to the conductivity the presence of a small group of bulk carriers was registered. For 3D-pocket Berry phase was identified as zero, which is a characteristic of trivial metallic states. [ABSTRACT FROM AUTHOR] more...
- Published
- 2018
- Full Text
- View/download PDF
30. Temperature Dependence of Renormalized Spin Susceptibility for Interacting 2D Electrons in Silicon.
- Author
-
Pudalov, V. M. and Gershenson, M. E.
- Subjects
- *
ELECTRON spin , *TWO-dimensional electron gas , *SHUBNIKOV-de Haas effect , *METAL-insulator transitions , *ELECTRIC properties of silicon - Abstract
By using Shubnikov-de Haas oscillations in crossed magnetic fields, we measured the temperature dependence of the renormalized spin susceptibility χi∗(T)
for strongly interacting itinerant 2D electrons in silicon. The weak δχi∗(T) dependence, only a few percent over the range T = (0.1 − 1)K , agrees qualitatively with the predicted interaction corrections. However, in strong in-plane magnetic fields, theχ ∗(T ) dependence does not vanish or weaken as expected for the interaction corrections. We found that the susceptibility variations are correlated with theT -dependence of the density of itinerant electrons extracted from the magnetooscillation period. We conclude therefore that the χi∗(T)dependence is affected by a T -dependent exchange of electrons between the subsystems of itinerant and localized electrons which are in thermodynamic equilibrium. [ABSTRACT FROM AUTHOR] more...- Published
- 2018
- Full Text
- View/download PDF
31. Germanium quantum well with two subbands occupied: Kinetic properties.
- Author
-
Berkutov, I. B., Andrievskii, V. V., Komnik, Yu. F., and Mironov, O. A.
- Subjects
- *
QUANTUM wells , *SILICON compounds , *CHEMICAL synthesis , *GERMANIUM compounds synthesis , *SHUBNIKOV-de Haas effect , *LANDAU levels , *HETEROSTRUCTURES - Abstract
Multisubband transport of the p-type Si0.4Ge0.6/Ge/Si0.4Ge0.6 heterostructure has been investigated by means of magnetotransport measurements at low temperatures and high magnetic fields. Two frequency Shubnikov-de Haas oscillations indicate occupation of two subbands. This allows us to determine the densities and mobilities of the charge carriers on each subband. Shubnikov-de Haas oscillations reveal two 2D conduction subbands with carrier effective masses of 0.112m0 and 0.131m0. The quantum Hall ferromagnetic states which results from the crossing of two Landau levels with opposite spin and different subband was observed in SiGe systems for the first time. [ABSTRACT FROM AUTHOR] more...
- Published
- 2017
- Full Text
- View/download PDF
32. Berry phase shift from 2π to π in bilayer graphene by Li-intercalation and sequential desorption.
- Author
-
Ryota Akiyama, Yuma Takano, Yukihiro Endo, Satoru Ichinokura, Ryosuke Nakanishi, Kentaro Nomura, and Shuji Hasegawa
- Subjects
- *
GEOMETRIC quantum phases , *GRAPHENE , *SHUBNIKOV-de Haas effect , *ULTRAHIGH vacuum , *CYCLOTRONS - Abstract
We have found that the Berry phase of bilayer graphene becomes π from 2π estimated by Shubnikov-de Haas oscillations when the A-B stacked pristine bilayer graphene experiences the Li-intercalation and sequential Li-desorption process in ultrahigh vacuum. Furthermore, the mobility of such processed bilayer graphene increases around four times larger, 8000 cm²/V.s, than that of the pristine bilayer graphene. This is mainly due to increment of the scattering time and decrement of the cyclotron mass, which can be interpreted as a result of the change of the stacking structure of bilayer graphene from A-B to A-A, corresponding to a change from the parabolic to the linear band dispersion. [ABSTRACT FROM AUTHOR] more...
- Published
- 2017
- Full Text
- View/download PDF
33. Study of the 'metal-insulator' transition induced by the impurity fluctuation potential using the Shubnikov-de Haas effect.
- Author
-
Oveshnikov, L., Davydov, A., Kulbachinskii, V., and Aronzon, B.
- Abstract
Heterostructures with a GaAs/InGaAs/GaAs quantum well and aMn magnetic impurity layer separated from it, which have different conductivity types, are studied. At a Mn content not exceeding the amount corresponding to 0.5 monolayer of MnAs, a percolation cluster formed in the quantum well plane is not simply connected, but consists of metal drops separated by low-conductivity interspaces. Despite the absence of the simply connected conducting channel, Shubnikov-de Haas oscillations are observed in all studied systems, which are controlled by carrier properties in conducting drops, independent of Mn content. The estimate of drop sizes corresponds to theoretical values. [ABSTRACT FROM AUTHOR] more...
- Published
- 2017
- Full Text
- View/download PDF
34. Experimental detection of quantum oscillations of anomalous Hall resistance in mercury selenide crystals with cobalt impurities.
- Author
-
Lonchakov, A. T., Bobin, S. B., Deryushkin, V. V., Okulov, V. I., Govorkova, T. E., Neverov, V. N., Pamyatnykh, E. A., and Paranchich, L. D.
- Subjects
- *
OSCILLATION theory of differential equations , *QUANTUM dots , *SHUBNIKOV-de Haas effect , *FLUCTUATIONS (Physics) , *COBALT , *INDUSTRIAL contamination - Abstract
Quantum oscillations of the anomalous component of Hall resistance with an amplitude exceeding the amplitude of the Shubnikov-de Haas oscillations of transverse magnetoresistance are observed in mercury selenide crystals doped with low concentrations of cobalt impurity. In accordance with the predictions of the Hall effect theory for systems with spontaneous spin polarization of hybridized donor electrons, the observed oscillations correspond to magnetic quantum oscillations caused by the thermodynamic anomalous Hall effect. [ABSTRACT FROM AUTHOR] more...
- Published
- 2017
- Full Text
- View/download PDF
35. Thermoelectric properties, Shubnikov-de Haas effect and mobility of charge carriers in bismuth antimony tellurides and selenides and nanocomposite based on these materials.
- Author
-
Kulbachinskii, V. A., Kytin, V. G., Kudryashov, A. A., Lunin, R. A., and Banerjee, A.
- Subjects
- *
SELENIDES , *BISMUTH telluride , *SHUBNIKOV-de Haas effect , *CHARGE carriers , *NANOCOMPOSITE materials , *GALVANOMAGNETIC effects - Abstract
We describe here the study of the Shubnikov-de Haas effect and thermoelectric properties of p-(Bi0.5Sb0.5)2Te3 single crystals doped with Ga, n-Bi2-xTlxSe3 and p-Sb2-xTlxTe3. Using Fourier spectra of the oscillations we calculated the mobility of charge carriers and its variation upon doping. We found that Ga has a donor effect in p-(Bi0.5Sb0.5)2Te3, Tl is an acceptor in n-Bi2-xTlxSe3 and increases the mobility of electrons, while in p-Sb2-xTlxTe3, Tl is a donor and decreases the mobility of holes. We consider the evolution of the defectiveness of crystals that leads to the observed effects. We also synthesized and investigated nanocomposites of solid solutions Sb2Te3-xSex (0
more... - Published
- 2017
- Full Text
- View/download PDF
36. Annealing effects on the properties of InGaAsN/GaAsSb type-II quantum well diodes grown on InP substrates.
- Author
-
Kawamura, Y., Shishido, I., Tanaka, S., and Kawamata, S.
- Subjects
- *
QUANTUM wells , *QUANTUM well devices , *MOLECULAR beam epitaxy , *ELECTROLUMINESCENCE , *SHUBNIKOV-de Haas effect , *MAGNETORESISTANCE - Abstract
Annealing effects on the properties of InGaAsN/GaAsSb type-II quantum well (QW) diodes grown on InP substrates by molecular beam epitaxy (MBE) were studied. It was found that the peak of electroluminescence (EL) shows drastic red-shift and the reverse-biased current of the current-voltage ( I- V) characteristic of the type-II QW diode increases by the annealing. In addition, we found that the electron effective mass of the InGaAsN layer of the type-II InGaAsN/GaAsSb multiple quantum wells (MQWs) estimated by the temperature dependence of the amplitude of the Shubnikov-de Haas (SdH) oscillations decreases by the annealing. The mechanism of the observed annealing effects was discussed. [ABSTRACT FROM AUTHOR] more...
- Published
- 2017
- Full Text
- View/download PDF
37. Properties of Doped GaSb Whiskers at Low Temperatures.
- Author
-
Khytruk, Igor, Druzhinin, Anatoly, Ostrovskii, Igor, Khoverko, Yuriy, Liakh-Kaguy, Natalia, and Rogacki, Krzysztof
- Subjects
GALLIUM antimonide ,METALLIC whiskers ,SUPERCONDUCTIVITY ,SHUBNIKOV-de Haas effect ,METAL-insulator transitions - Abstract
Temperature dependencies of GaSb whiskers' resistance doped with Te to concentration of 1.7 × 10 cm were measured in temperature range 1.5-300 K. At 4.2 K temperature, a sharp drop in the whisker resistance was found. The observed effect is likely connected with the contribution of two processes such as the electron localization in the whiskers and transition in superconducting state at temperature below 4.2 K. The whisker magnetoconductance is considered in the framework of weak antilocalization (WAL) model and connected with subsurface layers of the whiskers. The Shubnikov-de Haas (SdH) oscillatory effect is observed in high-quality n-type GaSb whiskers with tellurium doping concentration near the metal-insulator transition (MIT) for both longitudinal and transverse magnetoresistance. [ABSTRACT FROM AUTHOR] more...
- Published
- 2017
- Full Text
- View/download PDF
38. On the berry phase in quantum oscillations observed in 3D topological insulators.
- Author
-
Vedeneev, S.
- Subjects
- *
OSCILLATIONS , *TOPOLOGICAL insulators , *CHARGE carriers , *SHUBNIKOV-de Haas effect , *FERMI surfaces - Abstract
It is demonstrated that the copper-doped high-quality Bi Se single crystals with a high density of bulk charge carriers are certainly 3D topological insulators. The analysis of quantum Shubnikov−de Haas (SdH) oscillations reveals that these materials simultaneously exhibit two types of such oscillations determined by the Landau levels related to both the 3D and 2D Fermi surfaces. [ABSTRACT FROM AUTHOR] more...
- Published
- 2016
- Full Text
- View/download PDF
39. Robust quantum oscillations with non-zero Berry phase in Bi2Te3.
- Author
-
Barua, Sourabh and Rajeev, K.P.
- Subjects
- *
MAGNETORESISTANCE , *OSCILLATIONS , *SHUBNIKOV-de Haas effect , *SINGLE crystals , *MAGNETIC fields , *DIRAC function , *FERMI surfaces - Abstract
We performed angle dependent magnetoresistance study of a metallic single crystal sample of Bi 2 Te 3 . We find that the magnetoresistance is highly asymmetric in positive and negative magnetic fields for small angles between the magnetic field and the direction perpendicular to the plane of the sample. The magnetoresistance becomes symmetric as the angle approaches 90°. The quantum Shubnikov de-Haas oscillations are symmetric and show signatures of topological surface states with Dirac dispersion in the form of non-zero Berry phase. However, the angular dependence of these oscillations suggests a complex three dimensional Fermi surface as the source of these oscillations, which does not exactly conform with the six ellipsoidal model of the Fermi surface of Bi 2 Te 3 . We attribute the asymmetry in the magnetoresistance to a mixing of the Hall voltage in the longitudinal resistance due to the comparable magnitude of the Hall and longitudinal resistance in our samples. This provides a clue to understanding the asymmetric magnetoresistance often seen in this and similar materials. Moreover, the asymmetric nature evolves with exposure to atmosphere and thermal cycling, which we believe is either due to exposure to atmosphere or thermal cycling, or both affecting the carrier concentration and hence the Hall signal in these samples. However, the quantum oscillations seem to be robust against these factors which suggests that the two have different origins. [ABSTRACT FROM AUTHOR] more...
- Published
- 2016
- Full Text
- View/download PDF
40. Magnetotransport in thin epitaxial BiSe films.
- Author
-
Oveshnikov, L., Prudkoglyad, V., Nekhaeva, E., Kuntsevich, A., Selivanov, Yu., Chizhevskii, E., and Aronzon, B.
- Subjects
- *
BISMUTH selenide , *METALLIC films , *MAGNETIC fields , *SUBSTRATES (Materials science) , *SHUBNIKOV-de Haas effect - Abstract
The magnetoconductivity of thin BiSe films covered by a protective Se layer and grown at (111) BaF substrates is studied. It is shown that the negative magnetoconductivity observed at low magnetic fields and caused by the effect of weak antilocalization, as well as the Shubnikov−de Haas oscillations at higher fields, is determined only by the magnetic field component perpendicular to the film plane. The obtained experimental results can be reasonably interpreted under the assumption that the studied films exhibit two-dimensional topologically protected electron states. Moreover, the contribution of these states to the total conductivity turns out to be the dominant one. [ABSTRACT FROM AUTHOR] more...
- Published
- 2016
- Full Text
- View/download PDF
41. Kinetic phenomena in organic conductors in high magnetic fields (Review Article).
- Author
-
Peschansky, V. G. and Stepanenko, D. I.
- Subjects
- *
ANISOTROPY , *MAGNETORESISTANCE , *OSCILLATIONS , *DE Haas-van Alphen effect , *SHUBNIKOV-de Haas effect , *ELECTROMAGNETIC waves , *ORGANIC conductors - Abstract
A review of experimental and theoretical studies of transport phenomena in strongly anisotropic organic conductors is presented. Considerable attention is paid to the phenomena that are specific to quasi-2D and quasi-1D conductive structures and have no analogues both in ordinary metals and in truly 2D or 1D conducting systems. Angular magnetoresistance oscillations, de Haas-van Alphen and Shubnikov-de Haas phenomena, high-temperature quantum oscillations of the magnetoresistance, and high-frequency resonances, including those arising due to the motion of electrons open trajectories, are discussed. The resonant angular oscillations of high-frequency conductivity and weakly damped electromagnetic waves in quasi-2D organic conductors under strong spatial dispersion are considered. [ABSTRACT FROM AUTHOR] more...
- Published
- 2016
- Full Text
- View/download PDF
42. High field magneto-transport in two-dimensional electron gas LaAlO3/SrTiO3.
- Author
-
Ming Yang, Kun Han, Torresin, Olivier, Pierre, Mathieu, Shengwei Zeng, Zhen Huang, Venkatesan, T. V., Goiran, Michel, Coey, J. M. D., Ariando, and Escoffier, Walter
- Subjects
- *
MAGNETIC fields , *MAGNETORESISTANCE , *SHUBNIKOV-de Haas effect , *ELECTRIC resistance , *ELECTRICAL resistivity - Abstract
The transport properties of the complex oxide LaAlO3/SrTiO3 interface are investigated under a high magnetic field (55 T). Small oscillations of the magnetoresistance with altered periodicity are observed when plotted versus the inverse magnetic field. We attribute this effect to Rashba spin-orbit coupling which remains consistent with large negative magnetoresistance when the field is parallel to the sample plane. A large inconsistency between the carrier density extracted from Shubnikov-de Haas analysis and from the Hall effect is explained by the contribution to transport of at least two bands with different mobilities. [ABSTRACT FROM AUTHOR] more...
- Published
- 2016
- Full Text
- View/download PDF
43. High field magneto-transport in two-dimensional electron gas LaAlO3/SrTiO3.
- Author
-
Ming Yang, Kun Han, Torresin, Olivier, Pierre, Mathieu, Shengwei Zeng, Zhen Huang, Venkatesan, T. V., Goiran, Michel, Coey, J. M. D., Ariando, and Escoffier, Walter
- Subjects
MAGNETIC fields ,MAGNETORESISTANCE ,SHUBNIKOV-de Haas effect ,ELECTRIC resistance ,ELECTRICAL resistivity - Abstract
The transport properties of the complex oxide LaAlO
3 /SrTiO3 interface are investigated under a high magnetic field (55 T). Small oscillations of the magnetoresistance with altered periodicity are observed when plotted versus the inverse magnetic field. We attribute this effect to Rashba spin-orbit coupling which remains consistent with large negative magnetoresistance when the field is parallel to the sample plane. A large inconsistency between the carrier density extracted from Shubnikov-de Haas analysis and from the Hall effect is explained by the contribution to transport of at least two bands with different mobilities. [ABSTRACT FROM AUTHOR] more...- Published
- 2016
- Full Text
- View/download PDF
44. Td-MoTe2: A possible topological superconductor.
- Author
-
Luo, X., Chen, F. C., Zhang, J. L., Pei, Q. L., Lin, G. T., Lu, W. J., Han, Y. Y., Xi, C. Y., Song, W. H., and Sun, Y. P.
- Subjects
- *
SINGLE crystals , *MAGNETIC fields , *SHUBNIKOV-de Haas effect , *MAGNETORESISTANCE , *LANDAU theory , *SUPERCONDUCTIVITY - Abstract
We measured the magnetoresistivity properties of Td-MoTe2 single crystal under the magnetic field up to 33 T. By analyzing the Shubnikov-de Haas oscillations of the longitudinal resistance Δρxx, a linear dependence of the Landau index n on 1/B is obtained. The intercept of the Landau index plot is 0.47, which is between 3/8 and 1/2. This clearly reveals a nontrivial π Berry's phase, which is a distinguished feature of the surface state in Td-MoTe2 single crystal. Accompanied by the superconductivity observed at TC=0.1K, Td-MoTe2 may be a promising candidate of the topological superconductor and opens a door to study the relationship between the superconductivity and topological physics. [ABSTRACT FROM AUTHOR] more...
- Published
- 2016
- Full Text
- View/download PDF
45. Influence of Thickness on the Electrical Transport Properties of Exfoliated BiTe Ultrathin Films.
- Author
-
Mo, D., Wang, W., and Cai, Q.
- Subjects
EXFOLIATION (Geology) ,MOBILITY (Structural dynamics) ,THICKNESS measurement ,SHUBNIKOV-de Haas effect ,DIRAC equation ,NANOSTRUCTURED materials - Abstract
In this work, the mechanical exfoliation method has been utilized to fabricate BiTe ultrathin films. The thickness of the ultrathin films is revealed to be several tens of nanometers. Weak antilocalization effects and Shubnikov de Haas oscillations have been observed in the magneto-transport measurements on individual films with different thickness, and the two-dimensional surface conduction plays a dominant role. The Fermi level is found to be 81 meV above the Dirac point, and the carrier mobility can reach ~6030 cm/(Vs) for the 10-nm film. When the film thickness decreases from 30 to 10 nm, the Fermi level will move 8 meV far from the bulk valence band. The coefficient α in the Hikami-Larkin-Nagaoka equation is shown to be ~0.5, manifesting that only the bottom surface of the BiTe ultrathin films takes part in transport conductions. These will pave the way for understanding thoroughly the surface transport properties of topological insulators. [ABSTRACT FROM AUTHOR] more...
- Published
- 2016
- Full Text
- View/download PDF
46. Magneto-transport analysis of an ultra-low-density two-dimensional hole gas in an undoped strained Ge/SiGe heterostructure.
- Author
-
Laroche, D., Huang, S.-H., Chuang, Y., Li, J.-Y., Liu, C. W., and Lu, T. M.
- Subjects
- *
HETEROSTRUCTURES , *SCATTERING (Mathematics) , *SHUBNIKOV-de Haas effect , *DENSITOMETERS , *ELECTRON mobility - Abstract
We report the magneto-transport, scattering mechanisms, and effective mass analysis of an ultra-low density two-dimensional hole gas capacitively induced in an undoped strained Ge/Si0.2Ge0.8 heterostructure. This fabrication technique allows hole densities as low as p∼1.1×1010cm-2 to be achieved, more than one order of magnitude lower than previously reported in doped Ge/SiGe heterostructures. The power-law exponent of the electron mobility versus density curve, μ ∞ nα, is found to be α∼0.29 over most of the density range, implying that background impurity scattering is the dominant scattering mechanism at intermediate densities in such devices. A charge migration model is used to explain the mobility decrease at the highest achievable densities. The hole effective mass is deduced from the temperature dependence of Shubnikov-de Haas oscillations. At p∼1.0×1011cm-2, the effective mass m* is ∼0.105 m0, which is significantly larger than masses obtained from modulation-doped Ge/SiGe two-dimensional hole gases. [ABSTRACT FROM AUTHOR] more...
- Published
- 2016
- Full Text
- View/download PDF
47. On the quantum magnetic oscillations of electrical and thermal conductivities of graphene.
- Author
-
Alisultanov, Z.Z. and Reis, M.S.
- Subjects
- *
OSCILLATIONS , *QUANTUM thermodynamics , *ELECTRIC conductivity , *THERMAL conductivity , *FERMI surfaces - Abstract
Oscillating thermodynamic quantities of diamagnetic materials, specially graphene, have been attracting attention of the scientific community due to the possibility to experimentally map the Fermi surface of the material. These have been the case of the de Haas–van Alphen and Shubnikov–de Haas effects, found on the magnetization and electrical conductivity, respectively. In this direction, managing the thermodynamic oscillations is of practical purpose, since from the reconstructed Fermi surface it is possible to access, for instance, the electronic density. The present work theoretically explores the quantum oscillations of electrical and thermal conductivities of a monolayer graphene under a crossed magnetic and electric fields. We found that the longitudinal electric field can increase the amplitude of the oscillations and this result is of practical and broad interest for both, experimental and device physics. [ABSTRACT FROM AUTHOR] more...
- Published
- 2016
- Full Text
- View/download PDF
48. Quantum oscillation and nontrivial transport in the Dirac semimetal Cd3As2 nanodevice.
- Author
-
Haiyang Pan, Kang Zhang, Zhongxia Wei, Bo Zhao, Jue Wang, Ming Gao, Li Pi, Min Han, Fengqi Song, Xuefeng Wang, Baigeng Wang, and Rong Zhang
- Subjects
- *
SHUBNIKOV-de Haas effect , *CHEMICAL vapor deposition , *FERMIONS , *GEOMETRIC quantum phases , *DIRAC function - Abstract
Here, we report on the Shubnikov-de Haas oscillation in high-quality Cd3As2 nanowires grown by a chemical vapor deposition approach. The dominant transport of topological Dirac fermions is evident by the nontrivial Berry phase in the Landau Fan diagram. The quantum oscillations rise at a small field of 2 T and preserves up to 100 K, revealing a sizeable Landau level gap and a device mobility of 2138 cm2V–1 s–1. The angle-variable oscillations indicate the isotropy of the bulk Dirac transport. The large estimated mean free path makes the Cd3As2 nanowire a promising platform for the one-dimensional transport of Dirac semimetals. [ABSTRACT FROM AUTHOR] more...
- Published
- 2016
- Full Text
- View/download PDF
49. Magnetotransport study of (Sb1-xBix)2Te3 thin films on mica substrate for ideal topological insulator.
- Author
-
Yan Ni, Zhen Zhang, Nlebedim, Cajetan I., and Jiles, David C.
- Subjects
- *
THIN film research , *SHUBNIKOV-de Haas effect , *TOPOLOGICAL insulators - Abstract
We deposited high quality (Sb1-xBix)2Te3 on mica substrate by molecular beam epitaxy and investigated their magnetotransport properties. It is found that the average surface roughness of thin films is lower than 2 nm. Moreover, a local maxima on the sheet resistance is obtained with x = 0.043, indicating a minimization of bulk conductivity at this composition. For (Sb0.957Bi0.043)2Te3, weak antilocalization with coefficient of -0.43 is observed, confirming the existence of 2D surface states. Moreover Shubnikov-de Hass oscillation behavior occurs under high magnetic field. The 2D carrier density is then determined as 0.81 x 1016 m-2, which is lower than that of most TIs reported previously, indicating that (Sb0.957Bi0.043)2Te3 is close to ideal TI composition of which the Dirac point and Fermi surface cross within the bulk bandgap. Our results thus demonstrate the best estimated composition for ideal TI is close to (Sb0.957Bi0.043)2Te3 and will be helpful for designing TI-based devices. [ABSTRACT FROM AUTHOR] more...
- Published
- 2016
- Full Text
- View/download PDF
50. Galvanomagnetic effects in tellurium whiskers.
- Author
-
Averkiev, N. S., Berezovets, V. A., Savchenko, G. M., and Nikolaeva, A.
- Subjects
- *
GALVANOMAGNETIC effects , *TELLURIUM compounds , *METALLIC whiskers , *HALL effect , *SHUBNIKOV-de Haas effect - Abstract
Galvanomagnetic effects on Te samples were studied. The measurements were made in the broad range of temperatures (1.5 K ≤ T ≤ 80 K) and the values of the magnetic field induction. Shubnikov-de-Haas oscillations (SH) were detected in strong magnetic fields ( ωc τ ≫ 1, where ωc is the cyclotrone frequency); as well as anomalous temperature dependence of the Hall potential in classically weak ( ωc τ ≪ 1) magnetic fields. It was found out that the revealed SH oscillations are due to the Landau quantizations of the energy spectrum of three-dimensional (3D) charge carriers (holes) in the bulk samples under study. In the area of weak magnetic fields ( ωc τ ≪ 1), the effect of anomalous magnetoresistance was found, which was due to the weak localization of 3D holes in the samples . The theory of the Hall effect for holes in weak magnetic fields ( B < 0.2 Т) was developed. It is based on the solution of kinetic Boltzmann equation with the specific type of the collision integral; taking into account the carriers energy spectrum in tellurium. It was shown that the peculiarities of the Hall effect temperature dependence; which were found experimentally in weak magnetic fields; can be qualitatively explained if we bear in mind the complex structure of tellurium valence band. [ABSTRACT FROM AUTHOR] more...
- Published
- 2016
- Full Text
- View/download PDF
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