Valleytronics and negative differential resistance in cubic boron nitride: a first-principles study

TL;DR

This study uses first-principles calculations to reveal that cubic boron nitride exhibits negative differential resistance and favorable valleytronic properties, making it promising for high-power electronic applications.

Contribution

It provides the first detailed analysis of high-field transport and NDR in cubic boron nitride, highlighting its potential for valleytronics and transferred-electron devices.

Findings

c-BN shows negative differential resistance below 140 K

Strong energy dependence of scattering rates causes NDR

Intervalley scattering time in c-BN rivals diamond

Abstract

Cubic boron nitride (c-BN) is an ultrawide-bandgap semiconductor of significant interest for high-frequency and high-power electronics applications owing to its high saturation drift velocity and high electric breakdown field. Beyond transistors, devices exploiting the valley degree of freedom or negative differential resistance are of keen interest. While diamond has been found to have potential for these applications, c-BN has not been considered owing to a lack of knowledge of the relevant charge transport properties. Here, we report a study of the high-field transport and noise properties of c-BN using first-principles calculations. We find that c-BN exhibits an abrupt region of negative differential resistance (NDR) below 140 K, despite the lack of multi-valley band structure typically associated with NDR. This feature is found to arise from a strong energy dependence of the scattering rates associated with optical phonon emission. The high optical phonon energy also leads to an intervalley scattering time rivaling that of diamond. The negative differential resistance and long intervalley scattering time indicate the potential of c-BN for transferred-electron and valleytronic devices, respectively.