Interplay of bulk and edge states in transport of two-dimensional topological insulators

Abstract

We study transport in two-terminal metal/quantum spin-Hall insulator (QSHI)/metal junctions. We show that the conductance signals originating from the bulk and the edge contributions are not additive. While for a long junction the transport is determined by the edge states contribution, for a short junction, the conductance signal is built from both bulk and edge states in the ratio which depends on the width of the sample. Further, in the topological insulator regime the conductance for short junctions shows a non-monotonic behavior as a function of the sample length. Surprisingly this non-monotonic behavior of conductance can be traced to the formation of an effectively propagating solution which is robust against scalar disorder. Our predictions should be experimentally verifiable in HgTe QWs and Bi${}_2$Se${}_3$ thin films.

9 pages, 8 figures

References in corpus (6)

• Quantum Spin Hall Effect and Topological Phase Transition in HgTe Quantum Wells
• Quantum Spin Hall Insulator State in HgTe Quantum Wells
• Nonlocal edge state transport in the quantum spin Hall state
• The Quantum Spin Hall Effect: Theory and Experiment
• Finite size effects of helical edge states in HgTe/CdTe quantum wells
• Transversal Propagation Behaviors of Helical Edge States In a QSH System

Cited by in corpus (7)

• Spin-helical transport in normal and superconducting topological insulators
• Magnetic properties of HgTe quantum wells
• Proposal for an all-electrical measurement of crossed Andreev reflection in topological insulators
• Probing topological transitions in HgTe/CdTe quantum wells by magneto-optical measurements
• Interplay of chiral and helical states in a Quantum Spin Hall Insulator lateral junction
• Transport signatures of a quantum spin Hall - chiral topological superconductor junction
• Bulk transport through superconducting hybrid structures in HgTe quantum wells