Topologically Non-trivial RTD: Final Report

AbstractTopological insulators are materials that exhibit a unique quantum state of matter. This state is often referred to as the quantum spin hall state and has not been observed in any other type of material. This state of matter has very unique transport properties and in the last 10 years there has been much speculation about potential applications to take advantage of these properties. In this paper, the potential and applicability of a resonance tunneling diode constructed of topological insulator material is investigated. Conventional resonance tunneling diode properties are briefly reviewed and then used as comparison to a theoretical topological insulator resonance tunneling diode.

Introduction

First proposed in 1973 by Chang and Esaki, resonant tunneling has since become a very well understood and well utilized property in devices(Chang 1974). Due to the fabrication capabilities at the time, the devices that could be created were too thick and defective to properly utilize this effect. Early experiments on this effect were promising, but only showed weak features at unrealistically low temperatures. However, since then fabrication techniques have greatly improved and tunneling effects can now be well observed and utilized. One of the primary uses of this property is in the resonant tunneling diode(RTD), in which the double potential barrier system allows for strong diode control(Mizuta 1995).

In this report, the analysis of a theoretical RTD composed of topological insulator material will be carried out and used to compare the properties of this topologically non-trivial RTD to those of a conventional RTD. Topological insulators will be discussed in the following sections, but these materials exhibit unique edge state transport properties and could be useful in a RTD.