Edge reconstruction in Quantum Hall and Topological Insulators

by Yigal Meir

at Condensed Matter Theory Seminar

Wed, 01 Jun 2016, 13:30
Physics building (#54) room 207

Abstract

The edge structure of two dimensional systems is usually studied with sharp boundary conditions However the confining potential in physical systems is expected to be smooth It is shown that such a smooth confining potential may lead to edge reconstruction and formation of additional edge states This is demonstrated explicitly for the case of integer and fractional quantum Hall systems in strong magnetic field Moreover the effect is also manifested in two dimensional topological insulators TIs electronic materials that have a bulk band gap like an ordinary insulator but due to the combination of spin orbit interactions and time reversal symmetry TRS have protected conducting states on their edges These edge states are quasi one dimensional helical edge modes that are expected to come in counter propagating pairs due to the time reversal symmetry The time reversal protection of these edge states led to various suggested applications of TIs ranging from spintronics to quantum computation Here edge reconstruction leads to spontaneous TRS breaking a finite Hall resistance at zero magnetic field and possible spin current Such spontaneous TRS breaking may have important implications on transport properties as we demonstrate below and possible applications

Created on 27-05-2016 by Bar Lev, Yevgeny (ybarlev)
Updaded on 27-05-2016 by Bar Lev, Yevgeny (ybarlev)