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9 results on '"Grachtrup, D. Schulze"'

1. Field induced Lifshitz transition in UPt$_2$Si$_2$: Fermi surface under extreme conditions

Author

Grachtrup, D. Schulze, Steinki, N., Süllow, S., Cakir, Z., Zwicknagl, G., Krupko, Y., Sheikin, I., Jaime, M., and Mydosh, J. A.

Subjects
Condensed Matter - Strongly Correlated Electrons
Abstract

We have measured Hall effect, magnetotransport and magnetostriction on the field induced phases of single crystalline UPt$_2$Si$_2$ in magnetic fields up to 60\,T at temperatures down to 50\,mK. For the magnetic field applied along the $c$ axis we observe strong changes in the Hall effect at the phase boundaries. From a comparison to band structure calculations utilizing the concept of a dual nature of the uranium 5$f$ electrons, we find evidence for field induced topological changes of the Fermi surface due to at least one Lifshitz transition. Furthermore, we find a unique history dependence of the magnetotransport and magnetostriction data, indicating that the Lifshitz type transition is of a discontinuous nature, as predicted for interacting electron systems.

Published
2016
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2. Electronic ground state of MnB$_{4}$

Author

Steinki, N., Winter, J. L., Grachtrup, D. Schulze, Menzel, D., Süllow, S., Knappschneider, A., and Albert, B.

Subjects
Condensed Matter - Strongly Correlated Electrons, Condensed Matter - Materials Science
Abstract

Recent studies have dealt with the electronic and magnetic ground state properties of the tetraboride material MnB$_4$. So far, however, the ground state properties could not be established unambiguously. Therefore, here we present an experimental study on single-crystalline MnB$_4$ by means of resistivity and magnetization measurements. For this, we have developed a sample holder that allows four-point ac resistivity measurements on these very small ($\sim$\,100\,$\mu$m) samples. With our data we establish that the electronic ground state of MnB$_4$ is intrinsically that of a pseudo-gap system, in agreement with recent band structure calculations. Furthermore, we demonstrate that the material does neither show magnetic order nor a behavior arising from the vicinity to a magnetically ordered state, this way disproving previous claims.

Published
2016

4. Magnetic phase diagram and electronic structure of UPt 2 Si 2 at high magnetic fields: A possible field-induced Lifshitz transition

Author

Grachtrup, D. Schulze, Steinki, N., Sullow, S., Cakir, Z., Zwicknagl, G., Krupko, Y., Sheikin, Ilya, Jaime, M., Mydosh, J., Institut für Metallphysik und Nukleare Festkörperphysik, Technische Universität Braunschweig = Technical University of Braunschweig [Braunschweig], Sch Mines, Istanbul Tech Univ, Tech Univ Carolo Wilhelmina Braunschweig, Inst Math Phys, D-38106 Braunschweig, Germany, Laboratoire national des champs magnétiques intenses - Grenoble (LNCMI-G ), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), National High Magnetic Field Laboratory (MPA-NHMFL), and Los Alamos National Laboratory (LANL)

Subjects
[PHYS.COND.CM-SCE]Physics [physics]/Condensed Matter [cond-mat]/Strongly Correlated Electrons [cond-mat.str-el], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2017

7. Field-induced phases in UPt2Si2.

Author

Grachtrup, D. Schulze, Bleckmann, M., Willenberg, B., Süllow, S., Bartkowiak, M., Skourski, Y., Rakoto, H., Sheikin, I., and Mydosh, J. A.

Subjects
*ANTIFERROMAGNETISM, *GROUND state (Quantum mechanics), *MAGNETIC fields, *MAGNETIZATION, *CRYSTAL structure, *CRYSTALLOGRAPHY, *FERMI surfaces, *ELECTRIC fields
Abstract

The tetragonal compound UPt2SI2 has been characterized as a moderately mass-enhanced system with an anti-ferromagnetic (AFM) ground state below TN = 32 K. Here, we present an extensive study of the behavior in high magnetic fields. We have performed pulsed field magnetization and static field resistivity measurements on single crystalline samples UPt2SI2. Along the crystallographic a axis, at low temperatures, we find a metamagnetic-like transition in fields of the order 40 T, possibly indicating a first-order transition. Along the crystallographic c axis, in magnetic fields of B ≥ 24 T, we find distinct anomalies in both properties. From our analysis of the data we can distinguish new high-field phases above the AFM ground state. We discuss the emergence of these new phases in the context of Fermi surface effects and the possible occurrence of a Lifshitz or electronic topological transition, this in contrast to previous modelings of UPt2SI2 based on crystal electric field effects. [ABSTRACT FROM AUTHOR]

Published
2012
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8. High Field Magnetization of UPt2Si2.

Author

Grachtrup, D. Schulze, Bleckmann, M., Süllow, S., Willenberg, B., Rakoto, H., Skourski, Y., and Mydosh, J. A.

Subjects
*MAGNETIZATION, *CRYSTALLOGRAPHY, *MAGNETIC fields, *ELECTRIC fields, *ELECTROMAGNETIC fields
Abstract

High field magnetization measurements have been performed on single crystalline tetragonal UPt2Si2 for the crystallographic a and c directions. These results are compared to previous experiments and calculations based on a crystal electric field scheme. Our analysis indicates that the magnetization, while reproducing previous measurements, strongly deviates from the predictions of the crystal electric field scheme model for both crystallographic directions. This finding indicates that the magnetic behavior of UPt2Si2 is more adequately described within an itinerant approach. [ABSTRACT FROM AUTHOR]

Published
2010
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9. High Field Magnetization of UPt2Si2.

Author

Grachtrup, D. Schulze, Bleckmann, M., Süllow, S., Willenberg, B., Rakoto, H., Skourski, Y., and Mydosh, J. A.

Subjects
MAGNETIZATION, CRYSTALLOGRAPHY, MAGNETIC fields, ELECTRIC fields, ELECTROMAGNETIC fields
Abstract

High field magnetization measurements have been performed on single crystalline tetragonal UPt2Si2 for the crystallographic a and c directions. These results are compared to previous experiments and calculations based on a crystal electric field scheme. Our analysis indicates that the magnetization, while reproducing previous measurements, strongly deviates from the predictions of the crystal electric field scheme model for both crystallographic directions. This finding indicates that the magnetic behavior of UPt2Si2 is more adequately described within an itinerant approach. [ABSTRACT FROM AUTHOR]

Published
2010
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