Edge accumulation and currents of moment in 2D topological insulators

TL;DR

This paper investigates how spin (moment) currents and accumulation behave at the edges of 2D topological insulators, highlighting the unique edge phenomena and their distinction from bulk currents and conventional insulators.

Contribution

It provides a detailed analysis of edge spin accumulation and currents, emphasizing the role of edge states and the non-topological nature of bulk transverse currents.

Findings

Edge accumulation occurs only at edge states.

Bulk transverse currents can exist without topological protection.

No edge accumulation is associated with bulk currents.

Abstract

The Letter is analyzing bulk spin (moment) currents and spin (moment) accumulation at edges of a 2D topological insulator taking into account reflection from edges. Accumulation occurs only at edge states, which distinguish topological insulators from conventional ones. The band continuum can support the transverse bulk spin (moment) current, but it does not governed by the topological Chern number and may exist in a conventional insulator. There is no edge accumulation related with bulk currents.