Boron arsenide breaks the rules under pressure

Abstract

The semiconductor cubic boron arsenide (BAs) has thermal and electrical properties that rival those of silicon, making it a promising candidate for high-performance electronic components. Now scientists have revealed that BAs defies the rules of physics when in a pinch ( Nature 2022, DOI: 10.1038/s41586-022-05381-x ). Most crystalline materials conduct heat by transferring vibrational energy as acoustic waves between atoms in an ordered lattice. External pressure forces the atoms in a crystal lattice closer, making it easier to transfer vibrational energy between them. Experimental measurements of myriad materials all suggest that thermal conductivity increases with pressure until the material breaks down or changes phase, says Yongjie Hu, a chemist and mechanical engineer at the University of California, Los Angeles. Computational simulations predicted that BAs might buck the trend, so Hu decided to investigate how the semiconductor performs under pressure. Using a diamond anvil cell, Hu and his team squeezed a