Interference effect in the electronic transport of a topological insulator quantum dot

Abstract

Edge and bulk energy levels can coexist in a quantum dot (QD) made of a topological insulator. Interference effect will occur between bulk and edge levels and also between degenerate edge levels. It can be observed in the transport behavior. For the former, it acts as Fano interference with edge and bulk levels contributing continuous and resonant transport channels, respectively. Generally speaking, Fano interference can be realized in a two-armed junction with a single QD or a one-armed junction with at least two QDs. But here it is realized in a one-armed junction with a single QD. As for the interference between degenerate edge levels, it leads to a spin and space dependent scattering process. Spin of an incident electron will either be conserved or rotate about an axis for transmitting into different leads. It is determined by the local spin polarization of edge levels and the accumulated phase in transport paths in the QD. It may be used in the design of a spin field-effect transistor.

Advances and Prospects in Topological Nanoparticle Photonics

“…Strong coupling between a TINP and a quantum emitter has been proposed as a way to probe topological magnetoelectric effects . TI nanodisks have also been suggested as novel spin field-effect transistors . Quantum emitters tuned to a specific frequency in the vicinity of a TINP (such as illustrated in Figure d) will experience a greatly increased photonic LDOS, leading to enhanced spontaneous emission rates, quantum interference between spontaneous emission channels, and other benefits such as potentially enhanced energy transfer.…”