- This event has passed.
Klaus Morawetz: Anomalous transport in Weyl systems and graphene normally explained
December 13, 2018 @ 14:00 - 15:00
Nano Seminarjoint with Thursday, 13.12. 2018, 14.00,Lecture room F2 (1st floor), MFF UK, Ke Karlovu 5 |
Prof. Dr. Klaus Morawetz
Muenster University of Applied Sciences, Germany
Anomalous transport in Weyl systems and graphene normally explained
Te anomalous term in the balance of the chiral density can be rewritten as quantum current and does not violate classical conservation laws as it is claimed to be caused by quantum fluctuations. Moreover this term is derived from the quantum kinetic equations for systems with SU(2) structure within a completely conserving approach. Therefore the origin of this term is not a unique signal of symmetry-breaking terms in the field theoretical Lagrangian. Regularization-free density and pseudospin currents are calculated in Graphene and Weyl-systems realized as the infinite-mass limit of electrons with quadratic dispersion and a proper spin-orbit coupling. The intraband and interband conductivities are discussed and the optical conductivity agrees well with the experimental values using screened impurity scattering and an effective Zeeman field. The universal value of Hall conductivity is shown to be modified due to the Zeeman field.