Group seminar Theoretical Physics III

11.11.2020 10:45 a.m., room: S-439
Dr. Jernej Mravlje (Jožef Štefan Institute, Ljubljana, Slovenia)
Charge and spin-transport at high temperatures
18.11.2020 10:45 a.m., room: S-439
Nico Unglert, M.Sc.
The nodal-line semimetal ZrSiTe under external pressure - a DFT study
25.11.2020 10:45 a.m., room: S-439
Andreas Weh, M.Sc.
Half-metals in the presence of local many-body correlations
2.12.2020 10:45 a.m., room: S-439
Alyn James, MSc. (University of Bristol, UK)
Calculating DFT+DMFT wavefunction-dependent quantities using the new Elk-TRIQS interface
9.12.2020 10:45 a.m., room: S-439
Dr. Johannes Thiele (CEA, Saclay, France)
Neuromorphic computing: Overcoming computational challenges in AI with innovative hardware paradigms
16.12.2020 10:45 a.m., room: S-439
Priv.-Doz. Dr. Andreas Sinner (University of Augsburg)
Pairing transition in a double layer with interlayer Coulomb repulsion
20.1.2021 10:45 a.m., room: S-439
Dr. Firat Yilmaz
Thermal Hall conductance in time-reversal symmetry broken systems: A case study, impurity mechanism in chiral superconductors

The thermal Hall conductivities (THCs), Kij have extensively been studied in recent condensed matter experiments to investigate fractionalized quantum spin liquids [1], and quantum Hall systems [2]. The reason is that the non-Abelian fractional excitations could be characterized by a quantized fractional thermal Hall conductance. Similarly a transverse THC, i.e. Kxy, can spontaneously become non-zero for a time-reversal symmetry (TRS) broken system, and can have a contribution from topologically protected edge states. In this work, we decided to focus on an additional bulk effect in superconductors, the impurity mechanism, using the non-equilibrium quasiclassical Green's functions. Previously, the Kyx was found to be finite for the chiral p-wave superconductors [3] and vanishing for d-wave superconductors [4] for point impurities. Motivated by TRS broken d-wave superconductors, we generalized the Kxy calculations to i: finite temperatures, ii: finite size impurities.

We find that the impurity mechanism is dominant in Kxy at finite temperatures when compared to the topological contribution. At very low temperatures, the topological contribution constitutes the main portion of Kxy. There are two experimental signatures naturally emerge, Kxy has a non-monotonic temperature dependence and it can change sign as a function of temperature depending on the scattering process.

[1] Y. Kasahara, et. al., Nature 559, 227 (2018)

[2] M. Banerjee, et. al, Nature 559, 205 (2018)

[3] Yip, Sungkit, Superconductor Science and Technology 29, 085006 (2016)

[4] Arfi, B., H. Bahlouli, and C. J. Pethick., Physical Review B 39, 8959 (1989)

17.2.2021 10:45 a.m., room: S-439
Jernej Mravlje (IJS, Ljubljana)
The role of correlations and thermal disorder in transport properties of iron in the Earth's core
** Datum korrigiert: Mittwoch, 17. Februar 2021 **