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Thermoelectric materials enable efficient and clean conversion between heat and electricity, offering significant application prospects in waste heat recovery and solid‐state cooling. Lead selenide (PbSe) is a more abundant and cost‐effective alternative to PbTe with promising potential for mid‐temperature applications. However, things have changed very recently with the discovery of the traditional power generator PbSe being rather competitive as a thermoelectric cooler, opening new avenues for investigating this compound. This review aims to comb how the research achievements and promising performance of PbSe have shifted from medium to near‐room temperatures, by comprehensively discussing various strategies to enhance the thermoelectric efficiency at different temperature ranges. Subsequently, it is reviewed how these advances in materials have triggered deep investigations on constructing high‐efficiency power generation and cooling devices based on PbSe. Finally, a personal summary and outlook are presented on how to fully exploit the high‐ranged thermoelectric performance of PbSe materials and manufacture high‐efficiency power generators and coolers, thus promoting practical applications in the future. [ABSTRACT FROM AUTHOR]

The alteration of the lattice structure of monolayer graphene under strain and the resulting modulation of the band structure and the electronic properties are studied here in a view to figure out the electromechanical responses. The tight binding model (TBM) aided by effective-mass approximation (EMA) has effectively been used to study the impact of anisotropic strain. In this approach, the components of anisotropic strain tensor being connected to the amplitudes of electron hopping energy should alter the gauge field. The Dirac Hamiltonian is modified accordingly with the introduction of the gauge field term in it and is used to determine the evolution of strain-dependent dispersion energy. It is observed that under EMA, only 25% of anisotropic strain is sufficient to open up large band gap of ~ 3.5 eV when the strain is along zigzag direction, while it is 1.5 eV when the strain is along armchair direction. Therefore, by varying strain, it is possible to tune band gap, vis-a-vis electronic properties. The strain induced electron effective mass (EEM), density of states (DOS), carrier concentration, and intrinsic conductivity has been determined for the complete evaluation of the electronic properties of graphene sheet. [ABSTRACT FROM AUTHOR]

This study investigates the influence of hydrostatic pressure on structural, electronic, mechanical and optical properties of Sr3PX3 (X = Cl and Br) compounds, by using the first-principles density functional theory (DFT) within the pressure range of 0–30 GPa with a span of 10 GPa. For Sr₃PCl₃ and Sr3PBr3, the dynamical stability is confirmed by the fact that the phonon dispersion curves do not contain imaginary modes. Pressure-induced band gap alterations in Sr3PCl3 and Sr3PBr3 reveal semiconducting behavior: GGA measurements show a decrease from 1.70 eV and 1.55 eV at ambient pressure to 0.22 eV and 0.21 eV at 30 GPa; TB-mBJ results show a decrease from 2.73 eV and 2.40 to 1.07 eV and 0.92 eV. This supports their inverse relationship with pressure. The values of Debye and melting temperatures support their high-temperature applications. Effective mass also shows an inverse relationship with induced pressure. The bond length, lattice parameters, and cell volume reduces with pressure. They exhibit ductility, which is further enhanced by the applied pressure. These materials emerge as promising candidates for flexible optoelectronic devices. Optical properties like absorption coefficients, reflectivity, and dielectric functions were observed and found to be significantly influenced by applied pressure. The absorption spectra exhibit a significant redshift with increasing pressure, indicating enhanced potential for optoelectronic applications. Our detailed investigation sheds light on the tunability of Sr3PX3 (X = Cl and Br) properties under pressure, showcasing their potential for cutting-edge applications in optoelectronics and photovoltaics. [ABSTRACT FROM AUTHOR]

The β-Ag8GeSe6 crystallizes in the orthorhombic structure (Pma21 space group) at room temperature and is studied in the framework of density functional theory. The theoretical first-principle calculations of the electronic band structure, density of states, Seebeck coefficient, power factor, electrical conductivity and effective mass of the electron and hole of β-Ag8GeSe6 crystal are estimated by the generalized gradient approximation (GGA). A Perdew–Burke–Ernzerhof functional (PBE) was utilized. The effective mass of the electrons and holes was calculated based on the electronic band structure. Seebeck coefficient, power factor and electrical conductivity as functional temperature are studied and discussed. All obtained values at room temperature are compared with known experimental results. [ABSTRACT FROM AUTHOR]

Background: Modern combat sports, including boxing, categorize participants by body mass to ensure fairness and safety. The effective mass, or the ability to maximize body mass during a punch, significantly impacts striking force. This study aims to explore the relationship between effective mass and striking force in lead jab and rear cross punches of boxers. Material and methods: Thirteen male boxers with an average body mass of 90.6 kg and average height of 184 cm participated. The study employed an AMTI MC12-2K force plate (AMTI, Watertown, MA, USA) and Noraxon Ultium EMG sensors (Noraxon, Scottsdale, AZ, USA) to measure impact force and acceleration. Each boxer performed five maximum-force strikes with both lead jab and rear cross techniques. Results: The rear cross punch generated significantly higher ground reaction force (1709.28 ± 486.62 N) compared to the lead jab (1182.56 ± 250.81 N). However, effective mass values were similar for both punches: lead jab (18.95 ± 5.29 kg, 21.51% of body mass) and rear cross (18.50 ± 5.56 kg, 21.04% of body mass). Higher body mass and longer training tenure positively correlated with higher effective mass. An inverse relationship was found between fist acceleration and effective mass. Conclusions: Effective mass plays a crucial role in punch biomechanics, with similar utilization between lead jab and rear cross punches despite the latter's higher force. Training focused on optimizing body mass utilization and refining punch techniques can enhance punch effectiveness. [ABSTRACT FROM AUTHOR]

The properties of isospin-asymmetric cold nuclear matter are studied in terms of the relativistic mean-field theory in which, besides the fields of σ, ω, and ρ mesons, and the isovector, Lorentz-scalar field of the δ-meson is also taken into account. The properties of purely nucleonic np matter are studied as a function of the baryon density nB and the asymmetry parameter α, as well as the properties of electrically neutral β-equilibrium npe μ matter as a function of the baryon density nB. For different values of nB and a, such characteristics of np matter as the energy per baryon, the specific energy owing to isospin asymmetry, the effective proton and neutron masses, and the specific binding energy, are determined. It is shown that the energy owing to the asymmetry for a fixed value of α is a monotonically increasing function of the baryon density nB. For npem matter, the effective proton and neutron masses M p e f f , M n e f f , the specific binding energy Ebind, the symmetry energy Esym, the quantitative fraction of protons Yp = np/nB are studied, as well as the average meson fields σ ~ , ω ~ , δ ~ , and ρ ~ as functions of the baryon density nB. [ABSTRACT FROM AUTHOR]

Effective mass models are a powerful framework in mechanical design and qualification. They are a specialized modal model that use a base-acceleration input to yield the response of a base-mounted structure in single-axis dynamic environments. Applications include the computation of reaction forces of each mode of the base-mounted payload, the identification of the most "important" modes for loads analysis, and many others. Originally derived from a finite element model of the structure, many experimental techniques for computing effective mass models have also been developed. This work describes the derivation of a novel technique which utilizes the Craig-Bampton Modal framework to extract an effective mass model from a modal test and provides a much simpler formulation than previous methods while maintaining the accuracy of the computed effective mass model. Analytical and experimental demonstrations are provided along with practical recommendations for successful implementation. [ABSTRACT FROM AUTHOR]

By numerically solving the self-consistent system of the Schrödinger equations and Poisson electroneutrality, zone diagrams of LED heterostructures with In Ga N/GaN multiple quantum wells have been calculated. The effect of electron–phonon interaction, nonparabolicity of the dispersion relation, and hybridization of the wave function on the values of the effective mass of major charge carriers in the In Ga N/GaN quantum wells has been studied. The long-wave shift of 2D-plasmon resonances is associated with the temperature renormalization of the effective mass of two-dimensional carriers. To describe the temperature dependence of the effective mass, the function for the displacement of the 2D-plasmon resonance frequency is introduced. [ABSTRACT FROM AUTHOR]

The effective mass of bound polaron in an anisotropic quantum dot is calculated by using improved linear combination operator method. Under the influence of Rashba spin–orbit interaction, the effective mass of the polaron splits into two branches on the basis of zero spin. The effective mass of bound polaron is an increase function of electron–phonon coupling strength and Coulomb bound potential strength, and a decreasing function of velocity, transverse and longitudinal confinement lengths. The relations between the spin splitting effective mass and the velocity, transverse confinement length, longitudinal confinement length, electron–phonon coupling strength and Coulomb bound potential strength are also studied by us. Due to the heavy hole characteristics, the spin splitting effective mass is negative. [ABSTRACT FROM AUTHOR]

This study explores the variation of highly symmetric points in the band structure, revealing a shift from G-X symmetric K path to Z-G path under the influence of mechanical stress. Notably, the band gap decreased linearly with increasing mechanical stress, while the effective mass of the electron, heavy hole, and light hole exhibited different trends. The variation of band gap, effective mass of electron, heavy and light holes, electron affinity, dielectric constant in x and y direction has been found to be -0.1238 eV/GPa, -6E-3 1/GPa, -7.9E-3 1/GPa, 1.4E-2 1/GPa, 4.7e-2 eV/GPa, 7.3e-2 1/GPa and -10.3e-2 1/GPa, respectively. [ABSTRACT FROM AUTHOR]

Context: Due to advances in synthesizing lower-dimensional materials, there is the challenge of finding the wave equation that effectively describes quantum particles moving on 1D and 2D domains. Jensen and Koppe and Da Costa independently introduced a confining potential formalism showing that the effective constrained dynamics is subjected to a scalar geometry-induced potential; for the confinement to a curve, the potential depends on the curve's curvature function. Method: To characterize the π electrons in polyenes, we follow two approaches. First, we utilize a weakened Coulomb potential associated with a spiral curve. The solution to the Schrödinger equation with Dirichlet boundary conditions yields Bessel functions, and the spectrum is obtained analytically. We employ the particle-in-a-box model in the second approach, incorporating effective mass corrections. The π - π ∗ transitions of polyenes were calculated in good experimental agreement with both approaches, although with different wave functions. [ABSTRACT FROM AUTHOR]

It is well known that hexagonal Ge has a direct bandgap and exhibits excellent light emission. The structure and electrical characteristics of hex-GeSn alloys are investigated using an ab initio computation and the PBEsol-meta-GGA-mBJ function. In all alloys, the direct bandgap is observed. Due to the high radius of the Sn atom, when Sn content increases, the bandgap decreases and lattice parameters expand. Their spin–orbit, crystal field splitting and effective mass of electron and hole were also determined, indicating that the direct bandgap of hex-GeSn alloys has significant application in optoelectronic. [ABSTRACT FROM AUTHOR]

The p-type doping process during the growth of AlGaN nanowires directly influences the optoelectronic properties of the related devices. However, research on the p-type ionization mechanism in AlxGa1-xN nanowires remains limited. In this work, we utilize first principles calculations to investigate p-type doping in AlxGa1-xN nanowires under different structural variables (Al component, doping element, doping site, and doping concentration). Our results demonstrate that p-type doping in AlxGa1-xN nanowires is an endothermic process, and increased dopant concentration leads to a decrease in system stability. Moreover, we found that dopant atoms are easier to substitute for Ga atoms than Al atoms. Among the three doping elements (Zn, Be and Mg), Zn exhibits the most challenging doping difficulty, while Be shows the easiest doping process, with Mg falling in between. Crystal Orbital Hamilton Population (COHP) and bond population calculations reveal the mechanism for the variation in doping structure stability. Doping induces a rearrangement of energy level orbitals, resulting in changes in the band gap. Specifically, the valence band exhibits an overall upward trend crossing the Fermi level, showing the p-type conductive properties. Notably, a significant decrease in electron density near Mg and Be leads to the formation of p-type conductive properties. The changes in hole density and effective mass further confirm the formation of p-type conductivity after doping. Additionally, structures with lower Al composition exhibit higher doping ionization degrees. This study is expected to provide a theoretical basis for the growth, preparation, and application of optoelectronic devices based on p-type AlGaN nanowires.

The equation of state of asymmetric nuclear matter as well as the neutron and proton effective masses and their partial-wave and spin–isospin decomposition are analyzed within the Brueckner–Hartree–Fock approach. Theoretical uncertainties for all these quantities are estimated by using several phase-shift-equivalent nucleon–nucleon forces together with two types of three-nucleon forces, phenomenological and microscopic. It is shown that the choice of the three-nucleon force plays an important role above saturation density, leading to different density dependencies of the energy per particle. These results are compared to the standard form of the Skyrme energy density functional, and we find that it is not possible to reproduce the BHF predictions in the (S , T) channels in symmetric and neutron matter above saturation density, already at the level of the two-body interaction, and even more including the three-body interaction. [ABSTRACT FROM AUTHOR]

The Trachenko–Brazhkin equation of the minimal possible viscosity is analysed, emphasising its validity by the account of multibody interactions between flowing species through some effective masses replacing their true (bare) masses. Pressure affects the effective masses, decreasing them and shifting the minimal viscosity and the temperature at which it is attained to higher values. The analysis shows that effective masses in the Trachenko–Brazhkin equation are typically lighter compared bare masses; e.g., for tin (Sn) the effective mass is m = 0.21mSn, whereas for supercritical argon (Ar), it changes from m = 0.165mAr to m = 0.129mAr at the pressures of 20 and 100 MPa, respectively. [ABSTRACT FROM AUTHOR]

This study investigates the kinetic properties of both symmetrical and asymmetrical multilayer and nano-sized semiconductor structures. We develop a theoretical framework using various models and mathematical methods to solve the Schrödinger matrix equation for a system of electrons, taking into account the Bastard condition, which considers the difference in the effective masses of current carriers in adjacent layers. We analyze tunnel-coupled electronic states in quantum wells separated by a narrow tunneltransparent potential barrier. Our findings provide insights into the electronic properties of semiconductor structures, which are crucial for applications in micro- or nanoelectronics and other areas of solid-state physics. [ABSTRACT FROM AUTHOR]

Background: One of the elements of improving the striking power of combat sports athletes is the ability to use their body mass in an efficient manner; this can improve movement technique and thus increase combat effectiveness. Therefore, the aim of this study was to gain knowledge about the influence of the effective mass obtained on the strength of turning and side kicks in the context of lateralization. Material and methods: The study involved four adult taekwon-do ITF (International Taekwon-do Federation) competitors. Acceleration and force data were obtained by mounting a wireless IMU sensor manufactured by Noraxon, which was synchronized with a force plate. Results: The median force pressure values amounted to 2661.53 N for the turning kick and 4596.15 N for the side kick, with foot acceleration of 150.56 m/s2 and 74.34 m/s2, respectively. The calculated median effective mass for the turning kick was 20.12%, and for the side kick, it was 73.09% of the total body mass. The conducted analysis indicates a lack of statistically significant differences between the right and left leg in the obtained kinetic variable values (p > 0.05). Conclusions: Our research suggests that the side kick achieves, on average, higher force values than the turning kick. The noted correlation between the three variables informs us that the greater the effective mass, the greater the force pressure and the smaller the foot acceleration, which is consistent with other studies. The lack of lateralization in the limbs performing the kicks is consistent with another study. [ABSTRACT FROM AUTHOR]

This study examined the potential consequences of doping on Sr2YGaX2O7(X = Fe, Rh) photovoltaic properties. Density functional theory (DFT) was used to calculate pyrochlore oxides' energy band structure and optical characteristics using the full potential linearized augmented plane wave (FP-LAPW) method. The generalized gradient approximation (GGA + U) was utilized to treat the exchange and correlation potential. We studied the metallic atoms Fe, Rh, Y, and Ga orbital electronic states. The utilization of the complex dielectric function facilitated the computation of various optical properties such as the energy band dispersion statistics, absorption coefficient, reflectivity, energy loss function, refractive index, extinction coefficient, and real optical conductivity parameters. We employed Boltzmann transport theory to delve deeper into the electrical transport characteristics (specifically thermoelectric properties) of Fe and Rh-doped pyrochlore oxides in the temperature range of 0–800 K. It is observed that the Sr2YGaRh2O7 compound indicated higher values of ZT 0.9, 1.25 for 50 K and 800 K, respectively. Further, both the compounds exhibit p-type nature as their seebeck coefficient shows a positive region between 50 and 800 K. The materials with strong thermoelectric properties are assumed in high reflectivity zone and potentially effective in solar heating. [ABSTRACT FROM AUTHOR]

Background: Modern combat sports, including boxing, categorize participants by body mass to ensure fairness and safety. The effective mass, or the ability to maximize body mass during a punch, significantly impacts striking force. This study aims to explore the relationship between effective mass and striking force in lead jab and rear cross punches of boxers. Material and methods: Thirteen male boxers with an average body mass of 90.6 kg and average height of 184 cm participated. The study employed an AMTI MC12-2K force plate (AMTI, Watertown, MA, USA) and Noraxon Ultium EMG sensors (Noraxon, Scottsdale, AZ, USA) to measure impact force and acceleration. Each boxer performed five maximum-force strikes with both lead jab and rear cross techniques. Results: The rear cross punch generated significantly higher ground reaction force (1709.28 ± 486.62 N) compared to the lead jab (1182.56 ± 250.81 N). However, effective mass values were similar for both punches: lead jab (18.95 ± 5.29 kg, 21.51% of body mass) and rear cross (18.50 ± 5.56 kg, 21.04% of body mass). Higher body mass and longer training tenure positively correlated with higher effective mass. An inverse relationship was found between fist acceleration and effective mass. Conclusions: Effective mass plays a crucial role in punch biomechanics, with similar utilization between lead jab and rear cross punches despite the latter’s higher force. Training focused on optimizing body mass utilization and refining punch techniques can enhance punch effectiveness.

Using Tokuda's improved linear combination operator method and variational technique, the expression of the polaron effective mass in an parabolic quantum well is derived. Due to the spin-orbit interaction, the effective mass of polaron splits into two branches. The dependence of effective mass on temperature and mean number phonons is discussed by numerical calculation. The effective mass of polaron is an increasing function of temperature and mean number phonons. The absolute value of total spin splitting effective mass increases with the increase in temperature and spin-orbit coupling parameter, and decreases with the increase in velocity. Due to the heavy hole characteristic, the spin splitting effective mass is negative. [ABSTRACT FROM AUTHOR]

Using the linear combination operator method and variational technique improved by Tokuda, we obtain the expression of the effective mass of a strong coupled polaron in an anisotropic quantum dot. Due to the spin–orbit interaction, the effective mass of the polaron splits into two branches. The dependence of effective mass on temperature, electron–phonon coupling strength, transverse and longitudinal confinement lengths, and velocity is discussed by numerical calculation. The theoretical results indicate that the effective mass of the polaron is an increasing function of temperature and electron–phonon coupling strength, but a decreasing function of transverse confinement length, longitudinal confinement length, and velocity. The absolute value of spin splitting effective mass increases with the increase of temperature and spin–orbit coupling parameter, but decreases with the increase of transverse confinement length, longitudinal confinement length, and velocity. Due to the heavy hole characteristic, the spin splitting effective mass is negative. [ABSTRACT FROM AUTHOR]

The Ag8SnS6 crystal was synthesized by directly melting a high-purity stoichiometric mixture of elementary Ag, Sn, and S in a sealed quartz ampoule. This argyrodite crystallizes in the orthorhombic structure (Pna21 space group (No. 33)) at room temperature. The theoretical first-principle calculations of the electronic band structure and density of states of a αʹʹ-Ag8SnS6 crystal are estimated by the generalized gradient approximation (GGA) and local density approximation (LDA). A Perdew–Burke–Ernzerhof functional (PBE) and (PBEsol) were utilized for GGA calculation. All calculated parameters correlate well with known experimental data. Based on the electronic band structure, the effective mass of electrons and holes was calculated. The anisotropic behavior of electronic band structure is discussed.

The physical properties of crystalline compounds are highly essential for predicting their applications in various nanodevices. Density functional theory is very useful in that regard. Herein, some physical properties such as structural stability, and electronic, optical and mechanical properties of two-phase bulk WSe2 have been comparatively investigated by first principle calculations. Band structure calculations elucidate that the materials are indirect band gap semiconductors having band gap energy in the range 1-1.5 eV. It was observed that the hexagonal crystal has higher absorption coefficients compared to the trigonal phase. Analysis of elastic constants of the materials carried out using the Born criteria method indicates that all systems are mechanically stable at room temperature. Our findings are in close agreement with the previous experimental and theoretical results, this further suggests that the materials are promising in optoelectronics applications.

AgBi3S5 is a new n-type thermoelectric material that is environmentally friendly and composed of elements of earth-abundant, non-toxic and high performance-cost ratio. This compound features an intrinsically low thermal conductivity derived from its complex monoclinic structure. However, the terrible electrical transport properties greatly limited the improvement of thermoelectric performance. Most previous studies considered that carrier concentration is the main reason for low electrical conductivity and focused on improving carrier concentration by aliovalent ion doping. In this work, we found that the critical parameter that restricts the electric transport performance of AgBi3S5 was the extremely low carrier mobility instead of the carrier concentration. According to the Pisarenko relationships and density functional theory calculations, Nb doping can sharpen the conduction band of AgBi3S5, which contributes to reducing the effective mass and improving the carrier mobility. With a further increase of the Nb doping content, the conduction band convergence can enlarge the effective mass and preserve the carrier mobility. Combined with the decrease in lattice thermal conductivity due to the intensive phone scattering, a maximum ZT value of ∼0.50 at 773 K was achieved in Ag0.97Nb0.03Bi3S5, which was ∼109.6% higher than that of pure AgBi3S5. This work will stimulate the new exploration of high-performance thermoelectric materials in ternary metal sulfides.

CsSnBr3 nanocrystals are better than other lead-free perovskites because of their ease and low-cost synthesis, long-term function, and good stability. It is a suitable selection for use in tandem photodetectors. In this study, using the density functional theory, in the first stage, the elastic and electronic properties were calculated. Next, using the calculated quantities, the product of mobility-lifetime (µτ) of the charge carriers of CsSnBr3 was calculated. According to the results obtained, both of the electron and the hole have the lifetime-mobility product of an order 10-3 (V / cm2). The main reason for this can be attributed to the small effective mass of the charge carriers. However, this product has been reported for commercial detectors such as CdTe and CZT for electrons was of an order 10-3-10-2 and for holes in of an order 10-4-10-5. Therefore, due to the same of the product µτ in the CsSnBr3 crystal, the final pulse will be the sum of both charge carriers. As a result, the CsSnBr3 structure can show better potential for use in X-ray and gamma detectors.

Based on the band structure of TlGaTe compound, the extrema of the valence and conduction bands were determined and the tensor of the components of the inverse effective mass of electrons and holes was calculated. [ABSTRACT FROM AUTHOR]

In this work, the structural polymorphism and electro-optical characteristics of NaSbS2 ternary chalcogenide are realized using density functional theory (DFT). All of the NaSbS2 polymorphs are energetically stable based on the formation energy. The optimized lattice parameters of the monoclinic and triclinic structures and direct electronic bandgap (1.695 eV) of monoclinic structure are consistent with previous studies. Besides, the trigonal and triclinic structures are indirect bandgap (0.916 and 2.015 eV) semiconductors observed from electronic band structure. The higher degree of ionicity between Na and S atoms while strong covalency in the Sb-S bonds are confirmed from the charge and bond analysis. The lower value of electron-hole effective masses indicates higher carrier mobility leading to outstanding electrical conductivity. It was suggested that the polymorphs would be extremely desired to design Bragg reflectors and waveguides based on the reported high value of the real part of the dielectric constant and refractive index. These polymorphs will contribute significantly to being used as absorbers, as evidenced by their high absorption coefficient and photoconductivity and lower transmittance. All the polymorphs reflect significant optical anisotropy and birefringence, rendering them excellent for usage in the fabrication of waveguides, polarizers, and photonic devices. Thus, the projected good features of NaSbS2 polymorphs would play an essential role in the development of lead-free photovoltaic devices, including solar cells and other optoelectronic devices, and would be able to provide practical information for future theoretical and experimental studies.

Balancing the contradictory relationship between thermoelectric parameters, such as effective mass and carrier mobility, is a challenge to optimize thermoelectric performance. Herein, the exceptional thermoelectric performance is realized in GeTe through collaboratively optimizing the carrier and phonon transport via stepwise alloying Pb and CuSbSe2. The formation energy of Ge vacancy is efficiently bolstered by alloying Pb, which reduces carrier density and carrier scattering to maintain superior carrier mobility in GeTe. Additionally, CuSbSe2, acting as an n‐type dopant, further modulates carrier density and validly equilibrates carrier mobility and effective mass. Accordingly, the promising power factor of 45 µW cm−1 K−2 is achieved at 723 K. Meanwhile, point defects are found to significantly suppress phonons transport to descend lattice thermal conductivity by Pb and CuSbSe2 alloying, which barely impacts the carrier mobility. A combination with superior carrier mobility and lower lattice thermal conductivity, a maximum ZT of 2.2 is attained in Ge0.925Pb0.075Cu0.005Sb0.005TeSe0.01, which corresponds to a 100% promotion compared with that of intrinsic GeTe. This study provides a new indicator for optimizing carrier and phonon transport properties by balancing interrelated thermoelectric parameters. [ABSTRACT FROM AUTHOR]

Balancing the contradictory relationship between thermoelectric parameters, such as effective mass and carrier mobility, is a challenge to optimize thermoelectric performance. Herein, the exceptional thermoelectric performance is realized in GeTe through collaboratively optimizing the carrier and phonon transport via stepwise alloying Pb and CuSbSe2. The formation energy of Ge vacancy is efficiently bolstered by alloying Pb, which reduces carrier density and carrier scattering to maintain superior carrier mobility in GeTe. Additionally, CuSbSe2, acting as an n‐type dopant, further modulates carrier density and validly equilibrates carrier mobility and effective mass. Accordingly, the promising power factor of 45 µW cm−1 K−2 is achieved at 723 K. Meanwhile, point defects are found to significantly suppress phonons transport to descend lattice thermal conductivity by Pb and CuSbSe2 alloying, which barely impacts the carrier mobility. A combination with superior carrier mobility and lower lattice thermal conductivity, a maximum ZT of 2.2 is attained in Ge0.925Pb0.075Cu0.005Sb0.005TeSe0.01, which corresponds to a 100% promotion compared with that of intrinsic GeTe. This study provides a new indicator for optimizing carrier and phonon transport properties by balancing interrelated thermoelectric parameters. [ABSTRACT FROM AUTHOR]

In this paper, the interfacial electronic structures of the monolayer, bilayer, and magic-angle graphene/LiNbO3 heterostructures are calculated. The density, energy band, differential charge density, effective mass are calculated and analyzed for the model of structure. The results show that the interface material can adjust the state density, band width, electron concentration and effective mass of the electrons around the Fermi energy level. Therefore, we predict that this structure is feasible in principle for experimental preparation, and can improve the transfer efficiency of carrier, which can provide a high-speed carrier basis for the solar cells. [ABSTRACT FROM AUTHOR]

The Ag8GeS6 crystal was synthesized by the direct melting of the elementary Ag, Ge, and S high-purity grade stoichiometric mixture in a sealed quartz ampoule. This argyrodite crystallizes in orthorhombic structure [Pna21 space group (No. 33)] below ≈483 K. The theoretical first-principle calculations of the electronic band structure and density of states of an α'-Ag8GeS6 crystal are estimated by the generalized gradient approximation. The Perdew–Burke–Ernzerhof functional was utilized. All of the calculated parameters correlate well with the known experimental data. Based on the electronic band structure, the effective mass of the electrons and holes was calculated. The anisotropic behavior of electronic band structure is discussed. Temperature and carrier concentration dependence of the Seebeck coefficient is calculated. The temperature behavior of α'-Ag8GeS6 photoluminescence spectra is presented. The emission spectra are studied in the temperature range between 17 and 130 K and laser power excitation between 4 and 512 mW and in the spectral range of 750–1650 nm. Two main emission bands at ≈1.35 and ≈1.57 eV are observed and discussed. [ABSTRACT FROM AUTHOR]

The solid-state Cd0.75X0.25Te (X= Cu, Ag, and Au) solutions crystallize in the cubic structure and are studied in the framework of density functional theory. The theoretical first-principle calculations of the electronic band structure, density of states, and refractive index of solid-state Cd0.75X0.25Te (X= Cu, Ag, and Au) solutions are estimated by the generalized gradient approximation (GGA). A Perdew–Burke–Ernzerhof functional (PBE) was utilized. Formation energy is calculated based on the results of the total energy of the study samples. The effective mass of the electrons and holes was calculated based on the electronic band structure. The influence of atom substitution on electron conductivity and mobility is discussed. To study the optical properties was use a complex dielectric function ε(ħω). The spectral behaviour of the refractive index was calculated based on the dielectric function.

The equation of state of asymmetric nuclear matter as well as the neutron and proton effective masses and their partial-wave and spin–isospin decomposition are analyzed within the Brueckner–Hartree–Fock approach. Theoretical uncertainties for all these quantities are estimated by using several phase-shift-equivalent nucleon–nucleon forces together with two types of three-nucleon forces, phenomenological and microscopic. It is shown that the choice of the three-nucleon force plays an important role above saturation density, leading to different density dependencies of the energy per particle. These results are compared to the standard form of the Skyrme energy density functional, and we find that it is not possible to reproduce the BHF predictions in the (S,T) channels in symmetric and neutron matter above saturation density, already at the level of the two-body interaction, and even more including the three-body interaction.

The Trachenko–Brazhkin equation of the minimal possible viscosity is analysed, emphasising its validity by the account of multibody interactions between flowing species through some effective masses replacing their true (bare) masses. Pressure affects the effective masses, decreasing them and shifting the minimal viscosity and the temperature at which it is attained to higher values. The analysis shows that effective masses in the Trachenko–Brazhkin equation are typically lighter compared bare masses; e.g., for tin (Sn) the effective mass is m = 0.21mSn, whereas for supercritical argon (Ar), it changes from m = 0.165mAr to m = 0.129mAr at the pressures of 20 and 100 MPa, respectively.

Background: One of the elements of improving the striking power of combat sports athletes is the ability to use their body mass in an efficient manner; this can improve movement technique and thus increase combat effectiveness. Therefore, the aim of this study was to gain knowledge about the influence of the effective mass obtained on the strength of turning and side kicks in the context of lateralization. Material and methods: The study involved four adult taekwon-do ITF (International Taekwon-do Federation) competitors. Acceleration and force data were obtained by mounting a wireless IMU sensor manufactured by Noraxon, which was synchronized with a force plate. Results: The median force pressure values amounted to 2661.53 N for the turning kick and 4596.15 N for the side kick, with foot acceleration of 150.56 m/s2 and 74.34 m/s2, respectively. The calculated median effective mass for the turning kick was 20.12%, and for the side kick, it was 73.09% of the total body mass. The conducted analysis indicates a lack of statistically significant differences between the right and left leg in the obtained kinetic variable values (p > 0.05). Conclusions: Our research suggests that the side kick achieves, on average, higher force values than the turning kick. The noted correlation between the three variables informs us that the greater the effective mass, the greater the force pressure and the smaller the foot acceleration, which is consistent with other studies. The lack of lateralization in the limbs performing the kicks is consistent with another study.