Ultrasensitive Pressure Sensing with Boron Vacancy Defects in Hexagonal Boron Nitride: In-Situ Pressure Imaging of Two-Dimensional Heterostructures under High Pressure

Abstract

In-situ pressure imaging poses significant challenges due to strict experimental conditions. In this work, we integrate two-dimensional (2D) hexagonal boron nitride (hBN) with negative boron vacancy (V_B^–) spin defects directly into the chamber of the diamond anvil cell (DAC), enabling the first systematic investigation of their optical and spin properties under high pressure. Pressure-induced red-shifts of photoluminescence and reduced photon counts of the V_B^– defects are observed. The zero-field splitting parameter D of the V_B^– defects exhibits a linear pressure dependency at 57.4 MHz/GPa, with a pressure sensitivity of 0.32 $\mathrm{MPa}/\sqrt{\mathrm{Hz}}$, surpassing that of the nitrogen-vacancy centers in diamond and the silicon-vacancy centers in silicon carbon. Furthermore, by utilizing the V_B^– defects as ultrasensitive pressure quantum sensors, we have successfully mapped the inhomogeneous pressure distribution within an hBN/twisted double trilayer graphene/hBN device under compression via wide-field quantum imaging. The images reveal a pressure gradient increasing with loading. These results provide insight into the spin properties of V_B^– defects and the potential of in-situ pressure and magnetic imaging for 2D heterojunction devices under extreme conditions.