Intrinsic Piezoelectricity in Two-Dimensional Materials

TLDR

Piezoelectricity is widely used for robust electromechanical coupling in many sensors and actuators. Density‑functional calculations show that monolayer TMDCs such as BN, MoS₂, MoSe₂, MoTe₂, WS₂, WSe₂, and WTe₂ are piezoelectric, with coefficients spanning more than an order of magnitude and some exceeding bulk wurtzite values, suggesting their use in nanoscale sensors, actuators, and electronic devices.

Abstract

We discovered that many of the commonly studied two-dimensional monolayer transition metal dichalcogenide (TMDC) nanoscale materials are piezoelectric, unlike their bulk parent crystals. On the macroscopic scale, piezoelectricity is widely used to achieve robust electromechanical coupling in a rich variety of sensors and actuators. Remarkably, our density-functional theory calculations of the piezoelectric coefficients of monolayer BN, MoS2, MoSe2, MoTe2, WS2, WSe2, and WTe2 reveal that some of these materials exhibit stronger piezoelectric coupling than traditionally employed bulk wurtzite structures. We find that the piezoelectric coefficients span more than 1 order of magnitude, and exhibit monotonic periodic trends. The discovery of this property in many two-dimensional materials enables active sensing, actuating, and new electronic components for nanoscale devices based on the familiar piezoelectric effect.