High-pressure characterization of Ag$_3$AuTe$_2$: Implications for strain-induced band tuning
Abstract
Recent band structure calculations have suggested the potential for band tuning in a chiral semiconductor, AgAuTe, to zero upon application of negative strain. In this study, we report on the synthesis of polycrystalline AgAuTe and investigate its transport, optical properties, and pressure compatibility. Transport measurements reveal the semiconducting behavior of AgAuTe with high resistivity and an activation energy of 0.2 eV. The optical band gap determined by diffuse reflectance measurements is about three times wider than the experimental . Despite the difference, both experimental gaps fall within the range of predicted band gaps by our first-principles DFT calculations employing the PBE and mBJ methods. Furthermore, our DFT simulations predict a progressive narrowing of the band gap under compressive strain, with a full closure expected at a strain of -4% relative to the lattice parameter. To evaluate the feasibility of gap tunability at such substantial strain, the high-pressure behavior of AgAuTe was investigated by high-pressure X-ray diffraction up to 47 GPa. Mechanical compression beyond 4% resulted in a pressure-induced structural transformation, indicating the possibilities of substantial gap modulation under extreme compression conditions.
Cite
@article{arxiv.2405.19517,
title = {High-pressure characterization of Ag$_3$AuTe$_2$: Implications for strain-induced band tuning},
author = {Juyeon Won and Rong Zhang and Cheng Peng and Ravhi Kumar and Mebatsion S. Gebre and Dmitry Popov and Russell J. Hemley and Barry Bradlyn and Thomas P. Devereaux and Daniel P. Shoemaker},
journal= {arXiv preprint arXiv:2405.19517},
year = {2024}
}