Dresden 2020 – wissenschaftliches Programm
Die DPG-Frühjahrstagung in Dresden musste abgesagt werden! Lesen Sie mehr ...
TT 49.5: Vortrag
Mittwoch, 18. März 2020, 18:15–18:30, HSZ 103
"Energy stacks" of Quantum Hall transitions in dirty surfaces of topological superconductors — Björn Sbierski1, •Jonas Karcher2,3,4, and Matthew Foster4,5 — 1Department of Physics, University of California, Berkeley, CA 94720, USA — 2Institut für Nanotechnologie, Karlsruhe Institute of Technology, 76021 Karlsruhe, Germany — 3Institut für Theorie der Kondensierten Materie Karlsruhe Institute of Technology, 76128 Karlsruhe, Germany — 4Department of Physics and Astronomy, Rice University, Houston, Texas 77005, USA — 5Rice Center for Quantum Materials, Rice University, Houston, Texas 77005, USA
Normally QHPT states occur only at isolated energies; accessing them therefore requires fine-tuning of the electron density or magnetic field. In this work we show that QHPT states can be realized throughout an energy continuum, i.e. as an "energy stack" of critical states wherein each state in the stack exhibits QHPT phenomenology. The stacking occurs without fine-tuning at the surface of a class AIII topological phase, where it is protected by U(1) and time-reversal symmetries. Criticality is diagnosed by comparing numerics to universal results for the longitudinal Landauer conductance and multifractality at the QHPT. Results are obtained from an effective 2D surface field theory and from a bulk 3D lattice model. We demonstrate that the stacking of QHPT states is a robust phenomenon that occurs for AIII topological phases with both odd and even winding numbers. The latter conclusion may have important implications for the still poorly-understood logarithmic conformal field theory believed to describe the QHPT.