Article
Physics, Applied
Robert A. Robinson, Lujin Min, Seng Huat Lee, Peigang Li, Yu Wang, Jinguo Li, Zhiqiang Mao
Summary: In this study, researchers found a temperature-dependent violation of the WF law in the Heusler, ferromagnetic, Weyl semimetal Co2MnAl. The extreme magnitude and temperature dependence of the violation in Co2MnAl suggest that there may be multiple effects contributing to the violation in this system.
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2021)
Article
Physics, Nuclear
Kshitish Kumar Pradhan, Dushmanta Sahu, Ronald Scaria, Raghunath Sahoo
Summary: In this study, a hadron resonance gas with van der Waals interactions is investigated. Transport properties such as electrical and thermal conductivities are estimated by solving the Boltzmann transport equation, considering both attractive and repulsive interactions. The effects of baryochemical potential and temperature on these observables are explored, and comparisons are made with other theoretical models. Violation of the Wiedemann-Franz law is observed in the high-temperature regime of the hadron resonance gas, and diffusivities provide further insights into the system.
Article
Materials Science, Multidisciplinary
Pardeep Kumar Tanwar, Md Shahin Alam, Mujeeb Ahmad, Dariusz Kaczorowski, Marcin Matusiak
Summary: The thermal conductivity (??) of the Weyl semimetal NbP was studied with the thermal gradient and magnetic field applied parallel to the [0 0 1] direction. At low temperatures, ??(B) exhibits large quantum oscillations with frequencies matching two determined from the Shubnikov???de Haas effect. These frequencies originate from the electron pocket enclosing a pair of Weyl nodes. The amplitude of the oscillatory component of the thermal conductivity is significantly larger than the corresponding value calculated from the electrical conductivity using the Wiedemann-Franz law, possibly due to the chiral zero sound effect.
Article
Nanoscience & Nanotechnology
Jonah Waissman, Laurel E. Anderson, Artem Talanov, Zhongying Yan, Young J. Shin, Danial H. Najafabadi, Mehdi Rezaee, Xiaowen Feng, Daniel G. Nocera, Takashi Taniguchi, Kenji Watanabe, Brian Skinner, Konstantin A. Matveev, Philip Kim
Summary: The combination of reduced dimensionality, strong interactions, and topology in low-dimensional systems leads to many-body quantum phenomena. Thermal transport serves as a discriminating probe in quantum materials and devices, with the need for experimental methods to isolate electronic contributions. Measurements using noise thermometers and linear and nonlinear thermal transport reveal signatures of energy transport mediated by long-range interactions in one-dimensional electron systems.
NATURE NANOTECHNOLOGY
(2022)
Article
Physics, Multidisciplinary
Xuebo Zhou, Ping Zheng, Wei Wu, Yu Sui, Jianlin Luo
Summary: CrP has unique physical properties due to the nonsymmorphic symmetry of the space group, resulting in a four-fold degenerate band crossing at the Y point of the Brillouin zone. We conducted various measurements on CrP, including heat capacity, electrical and thermal transport, and extracted the electron thermal conductivity. The normalized Lorentz number decreases below 160 K due to differences in energy and momentum relaxation time during electron-phonon inelastic scattering, but begins to recover below 25.6 K due to the dominance of elastic scattering between electrons and defects at low temperatures.
Article
Nanoscience & Nanotechnology
Vikash Sharma, Gunadhor Singh Okram, Yung-Kang Kuo
Summary: We investigated the electrical and thermal transport properties of nickel nanoparticles with varying crystallite sizes. The nanoparticles exhibited a systematic metal to insulator transition, changing the conduction type and showing a colossal Seebeck coefficient and ultralow thermal conductivity. The analysis of electrical resistivity revealed a significant change in the electronic excitation spectrum, indicating the opening of an energy gap and the presence of cotunneling and Coulomb blockade of charge carriers. The Lorenz number also increased with decreasing crystallite size, demonstrating a violation of the Wiedemann-Franz law.
Article
Chemistry, Multidisciplinary
Danial Majidi, Martin Josefsson, Mukesh Kumar, Martin Leijnse, Lars Samuelson, Herve Courtois, Clemens B. Winkelmann, Ville F. Maisi
Summary: The Wiedemann-Franz law states that charge conductance and the electronic contribution to heat conductance are proportional. However, our experiments show that the heat conduction can be significantly lower than the predicted value due to quantum confinement and energy-selective transport properties in a semiconductor nanostructure. This opens up new possibilities for independently tailoring the thermal and electrical conduction properties.
Article
Chemistry, Physical
Adam Rycerz
Summary: The 2016 experiment by Crossno et al. found that the thermal conductivity of graphene violates the WF law at low temperatures, attributed to interactions between particles. Even at temperatures of few- or sub-kelvin, significantly enhanced thermal conductivity should appear, even when neglecting the role of interactions. Numerical results obtained within the Landauer-Buttiker formalism also support this finding.
Article
Nanoscience & Nanotechnology
Zhihui Lei, Wendong Liu, Wenkui Xing, Yingyue Zhang, Yongjia Liu, Peng Tao, Wen Shang, Benwei Fu, Chengyi Song, Tao Deng
Summary: In this work, we observed the size-dependent behavior of filler on the thermal and electrical conductivities of nacre-like graphene-conjugated conducting polymer films and demonstrated the tunability of the Lorenz constant in such films. These films showed high thermal and electrical conductivities, as well as good electromagnetic interference shielding performance. The findings provide new insights for designing flexible graphene-conjugated polymers with customizable thermal and electrical properties.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Materials Science, Multidisciplinary
Erik D. Kountz, Jiecheng Zhang, Joshua A. W. Straquadine, Anisha G. Singh, Maja D. Bachmann, Ian R. Fisher, Steven A. Kivelson, Aharon Kapitulnik
Summary: ErTe3 serves as a model system to study thermal transport in layered charge density wave materials. Thermal diffusivity, resistivity, and specific-heat data show a sharp decrease in thermal conductivity at the CDW transition temperature, while resistivity changes more gradually. In the critical regime, the behavior corresponds to a strongly coupled electron-phonon critical soup where traditional description is not possible.
Review
Physics, Multidisciplinary
Kamran Behnia
Summary: This paper discusses the relationship between electron-electron collisions and the electric resistivity of metals with respect to temperature, as well as the microscopic source of this phenomenon. By comparing it with the case of normal liquid He-3, the paper points out that the temperature dependence of Fermi liquid is the ultimate origin of the ubiquitous T-square electrical resistivity.
ANNALEN DER PHYSIK
(2022)
Article
Materials Science, Multidisciplinary
Qingan Yin, Zhanqiang Liu, Bing Wang, Kai Ma, Yukui Cai, Qinghua Song
Summary: A novel surface conductive active medium (SCAM) coating method is proposed to decrease the cutting temperature of Inconel 718. Experimental and theoretical results demonstrate that increasing the electrical conductivity of SCAM can reduce the temperature of cutting tool.
JOURNAL OF MATERIALS RESEARCH AND TECHNOLOGY-JMR&T
(2022)
Article
Physics, Applied
Marijn Lucas, Lev V. Levitin, Petra Knappova, Jan Nyeki, Andrew Casey, John Saunders
Summary: This study demonstrates that silver is an excellent material for thermal links in high-temperature ultra-low-temperature experiments operating at high magnetic fields.
JOURNAL OF LOW TEMPERATURE PHYSICS
(2023)
Proceedings Paper
Materials Science, Multidisciplinary
Narayan Gaonkar, R. G. Vaidya
Summary: In this study, we investigated the electrical conductivity, electronic thermal conductivity, and Wiedemann-Franz law in 2D phosphorene, considering the scattering of electrons by single in-plane and two out-of-plane flexural phonon processes. The Lorenz number in 2D phosphorene was found to deviate from the actual value with an increase in temperature. Furthermore, the electrical conductivity and electronic thermal conductivity of armchair and zigzag 2D phosphorene were observed to be anisotropic.
MATERIALS TODAY-PROCEEDINGS
(2022)
Article
Physics, Condensed Matter
E. V. Zavitaev, O. V. Rusakov, E. P. Chukhleb
Summary: The problem of the effect of deviation from the Wiedemann-Franz law on the electrical conductivity of a thin metal layer is solved for the first time. The admissible values of the layer thickness are found to be limited by the absence of quantum effects and the skin effect. A modified kinetic equation is used to account for the deviation of metal properties at low temperatures, considering electron-electron collisions and non-isotropic electron scattering. The study also analyzes the dependence of electrical conductivity on various factors and compares theoretical results to an alternative calculation method.
JOURNAL OF SURFACE INVESTIGATION
(2022)
Article
Physics, Applied
C. Back, V Cros, H. Ebert, K. Everschor-Sitte, A. Fert, M. Garst, Tianping Ma, S. Mankovsky, T. L. Monchesky, M. Mostovoy, N. Nagaosa, S. S. P. Parkin, C. Pfleiderer, N. Reyren, A. Rosch, Y. Taguchi, Y. Tokura, K. von Bergmann, Jiadong Zang
JOURNAL OF PHYSICS D-APPLIED PHYSICS
(2020)
Article
Chemistry, Multidisciplinary
Clifford Murray, Camiel van Efferen, Wouter Jolie, Jeison Antonio Fischer, Joshua Hall, Achim Rosch, Arkady V. Krasheninnikov, Hannu-Pekka Komsa, Thomas Michely
Article
Multidisciplinary Sciences
Felix Muenning, Oliver Breunig, Henry F. Legg, Stefan Roitsch, Dingxun Fan, Matthias Roessler, Achim Rosch, Yoichi Ando
Summary: The non-trivial topology of three-dimensional topological insulators leads to the appearance of unique gapped Dirac sub-band structures in nanowires, which are important for future Majorana qubits. These quantized sub-bands can be observed by tuning the chemical potential in the gate-voltage dependence of the resistance.
NATURE COMMUNICATIONS
(2021)
Article
Materials Science, Multidisciplinary
Jan Attig, Jinhong Park, Michael M. Scherer, Simon Trebst, Alexander Altland, Achim Rosch
Summary: This paper explores the universal physical properties of moire materials using statistical principles, focusing on the Fermi surface flat bands in moire structures, and examines the competition outcomes in these systems.
Article
Physics, Multidisciplinary
Nina del Ser, Lukas Heinen, Achim Rosch
Summary: In chiral magnets, a spatially homogeneous but oscillating magnetic field perpendicular to the propagation vector induces a net rotation of the texture around the vector, reminiscent of the motion of an Archimedean screw. This effect, proportional to the square of the field strength, can transport spin and charge, and can be resonantly enhanced by exciting internal modes of the helix. The helix can become unstable under stronger fields, forming a 'time quasicrystal' that oscillates in space and time.
Article
Chemistry, Multidisciplinary
Mariia Stepanova, Jan Masell, Erik Lysne, Peggy Schoenherr, Laura Koehler, Michael Paulsen, Alireza Qaiumzadeh, Naoya Kanazawa, Achim Rosch, Yoshinori Tokura, Arne Brataas, Markus Garst, Dennis Meier
Summary: Research on magnetic disclinations, dislocations, and domain walls in FeGe reveals unique responses that distinguish them from the helimagnetic background, proposing a new detection scheme using superconducting microcoils for topological spin textures and domain walls in device-relevant geometries.
Article
Physics, Multidisciplinary
Alla Bezvershenko, Catalin-Mihai Halati, Ameneh Sheikhan, Corinna Kollath, Achim Rosch
Summary: In this study, we proposed an approach to describe the Dicke transition of interacting many-particle systems strongly coupled to the light of a lossy cavity. By combining a mean-field approach with a perturbative treatment of fluctuations, we were able to determine the nature of the steady state, the thermal character of the transition, and the universal properties of the emerging self-organized states. Our results were validated through comparisons with time-dependent matrix-product-state calculations.
PHYSICAL REVIEW LETTERS
(2021)
Article
Physics, Multidisciplinary
Anne Matthies, Jinhong Park, Erez Berg, Achim Rosch
Summary: Investigated two Josephson-coupled topological quantum wires with Coulomb interactions, inducing Floquet Majorana modes through oscillating gate voltage, enabling encoding of three qubits in a sector with fixed electron parity. Avoided system instability by gradually increasing oscillation frequency.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Yongjian Wang, Henry F. Legg, Thomas Boemerich, Jinhong Park, Sebastian Biesenkamp, A. A. Taskin, Markus Braden, Achim Rosch, Yoichi Ando
Summary: Researchers have discovered that ZrTe5 crystals exhibit a gigantic magnetochiral anisotropy when they are in proximity to a topological quantum phase transition, which is the largest ever observed. The low carrier density, inhomogeneities, and torus-shaped Fermi surface induced by breaking of inversion symmetry in a Dirac material are argued to be central to explaining this extraordinary property.
PHYSICAL REVIEW LETTERS
(2022)
Article
Physics, Multidisciplinary
Aprem P. Joy, Achim Rosch
Summary: This paper explores the behavior of visons in perturbed Kitaev spin liquid, revealing different phenomena in ferromagnetic and antiferromagnetic models, and discusses the universal signatures of vison diffusion in quench experiments.
Article
Physics, Multidisciplinary
Phoebe Tengdin, Benoit Truc, Alexey Sapozhnik, Lingyao Kong, Nina del Ser, Simone Gargiulo, Ivan Madan, Thomas Schoenenberger, Priya R. Baral, Ping Che, Arnaud Magrez, Dirk Grundler, Henrik M. Ronnow, Thomas Lagrange, Jiadong Zang, Achim Rosch, Fabrizio Carbone
Summary: The rotation of a skyrmion crystal can be controlled by a faster method, which is achieved through magnetic oscillations triggered by laser pulses. This method has potential applications in the engineering of spin-based logical devices.
Article
Materials Science, Multidisciplinary
Jeyong Park, Lasse Gresista, Simon Trebst, Achim Rosch, Jinhong Park
Summary: Moire systems provide a highly tunable platform for engineering band structures and exotic correlated phases. A theoretical study of a single layer of graphene subject to a smooth moire electrostatic potential is conducted, and it is found that ultra-flat bands coexist with a triangular network of chiral one-dimensional channels. Effective interactions between localized modes with multiple degrees of freedom emerge from the flat bands, and the form of these interactions reflects the chirality and one-dimensional nature of the network. The study focuses on commensurate order stabilized by local two-site and chiral three-site interactions and explores the effects of quantum and classical fluctuations on the observed phases.
Article
Physics, Multidisciplinary
Camiel van Efferen, Jeison Fischer, Theo A. Costi, Achim Rosch, Thomas Michely, Wouter Jolie
Summary: In this study, a Kondo system based on a quantum confined state within a MoS2 grain boundary is described. The system allows for experimental resolution of the spectral function and its spatial modulation, as well as testing the predictive power of the Anderson model in Kondo physics.
Article
Materials Science, Multidisciplinary
Jinhong Park, Omri Golan, Yuval Vinkler-Aviv, Achim Rosch
Summary: This study investigates the response of quantum Hall states and other gapped chiral topological states to temperature gradients. The traditional approach of using a gravitational model to describe temperature gradients is found to be invalid for these states.
Article
Optics
Philipp S. Weiss, Dennis Hardt, Achim Rosch
Summary: It is a typical strategy to achieve adiabatic changes in multi-particle systems by varying parameters slowly over a large time scale t(r). The entropy production in diffusive systems at finite temperature is influenced by hydrodynamic modes, with different behaviors observed in different dimensions. Through simulating classical gas dynamics, the theoretical predictions regarding entropy production can be confirmed.
