2020/04/30 by Taiki Matsushita, Yuki Nagai, Satoshi Fujimoto
Physics and Astronomy · #Condensed matter physics #Hamiltonian (control theory) #Hermitian matrix #Landau quantization #Magnetic field #Physics #Quantum Mechanics and Non-Hermitian Physics #Quantum and electron transport phenomena #Quantum electrodynamics #Quantum mechanics #Quasiparticle #Scattering #Superconductivity #Topological Materials and Phenomena #Vortex #cond-mat.mes-hall #cond-mat.str-el
paper · pdf · doi:10.7566/jpsj.90.074703
published as J. Phys. Soc. Jpn. 90, 074703 (2021) · 8 pages,4 figures
arxiv created 2021/01/28 · openalex created_date 2021/02/01 · openalex publication_date 2021/06/04 · arxiv updated 2021/06/07 · openalex updated_date 2026/08/05
We investigate disorder effects on Landau levels in Dirac electron systems with the use of a non-Hermitian quasiparticle Hamiltonian formalism. This formalism reveals that spin-dependent scattering rates induce the spectrum collapse of Landau levels, i.e., the disappearance of the energy gaps between n-th and -n-th levels under a finite external magnetic field. The spectrum collapse occurs in both weak and strong magnetic field regimes, thus showing a reentrant behavior. Particularly, in the strong magnetic field regime, in contrast to naive expectation, the increase of a magnetic field stabilizes the spectrum collapse of Dirac Landau levels. Furthermore, it is revealed that the spectrum collapse is associated with the emergence of a vortex texture with a topological winding number of a complex energy spectrum of the non-Hermitian system.