A valleytronic diamond transistor: electrostatic control of valley-currents and charge state manipulation of NV centers

TL;DR

This paper demonstrates electrostatic control of valley-currents in diamond transistors and shows how to manipulate NV center charge states, advancing valleytronics and quantum information processing without external magnetic fields.

Contribution

It introduces a dual gate diamond transistor enabling all-electric control of valley-polarized states and NV center charge states, a novel approach in valleytronics and quantum device engineering.

Findings

Electrostatic control of valley-currents achieved in diamond transistors.

Separate modulation of charge and valley currents via gate voltages.

Valley-current charge state manipulation demonstrated on NV centers.

Abstract

The valley degree of freedom in many-valley semiconductors provides a new paradigm for storing and processing information in valleytronic and quantum-computing applications. Achieving practical devices require all-electric control of long-lived valley-polarized states, without the use of strong external magnetic fields. Attributable to the extreme strength of the carbon-carbon bond, diamond possesses exceptionally stable valley states which provides a useful platform for valleytronic devices. Using ultra-pure single-crystalline diamond, we here demonstrate electrostatic control of valley-currents in a dual gate field-effect transistor, where the electrons are generated with a short UV pulse. The charge -- and the valley -- current measured at receiving electrodes are controlled separately by varying the gate voltages. A proposed model based on drift-diffusion equations coupled through rate terms, with the rates computed by microscopic Monte Carlo simulations, is used to interpret experimental data. As an application, valley-current charge state modulation of nitrogen-vacancy (NV) centers is demonstrated.