Twist-Controlled Modulation of Quantum Emitters in a Van der Waals Bilayer

TL;DR

This paper demonstrates that twisting a van der Waals bilayer of hexagonal boron nitride can modulate embedded quantum emitters at room temperature, enabling tunable quantum photonic devices.

Contribution

It introduces a method to control quantum emitter properties via twist angle in hBN bilayers, combining theoretical modeling and experimental twisting.

Findings

Twist angle strongly influences quantum emitter emission properties.

Mechanical twisting achieves over 30 nm tunability of emission wavelength.

Twist-controlled modulation paves the way for programmable quantum photonic circuits.

Abstract

Stacking and twisting two dimensional materials has garnered enormous attention across the condensed matter and the nanophotonic communities. The surge of interest stems from the emergence of novel photophysical phenomena that arise due to the interlayer coupling of the individual layers. Here, we demonstrate that the twist degree of freedom can modulate a single quantum emitter at room temperature. We employ a van der Waals homobilayer of hexagonal boron nitride (hBN) and model the emission properties of quantum emitters as a function of the twist angle. Density functional theory results show that the embedded emitters are strongly influenced by the twist angle and the stacking of the top hBN layer. We consequently engineer these systems experimentally, and demonstrate in-situ tuning of embedded quantum emitters by mechanically twisting the top hBN layer, achieving tunability of over 30 nm (~ 100 meV). Our work demonstrates that mechanical twisting can be harnessed to modulate the embedded quantum emitters in a vdW material, marking a crucial step towards a programmable on-chip quantum circuitry.