Influence of Pressure on Phonon Properties of Indium Antimonide

Herein, experimental observation of the pressure-induced softening of the zone-edge transverse acoustical (TA(X)ze) phonon in the zincblende indium antimonide is for the first time reported. Experimental data allow for determination of Gr & uuml;neisen parameter for the TA(X)ze phonon mode. The density-functional theory calculations performed within quasiharmonic approximation at 0 K also reveal the softening of the TA(X)ze at high pressure, although the experimental value of its frequency shift is almost three times smaller than the theoretical one. In contrast, pressure dependences of optical phonons are well reproduced in our calculations. Similar calculations for GaSb and InP result in good agreement with available experimental data for optical and, as opposed to InSb, also for TA(X)ze phonons. The fact that the quasiharmonic theory works well for GaSb and InP may suggest that anharmonicity of acoustical phonons in these compounds is insignificant at room temperature. The possibility of enhanced anharmonicity of TA(X)ze phonon in InSb is discussed. The pressure of transition derived from experimentally determined shift of TA(X)ze frequency for InSb does not fit the recently proposed model of Weinstein working well for over 20 semiconductors, which also shows the specificity of InSb especially in comparison to other cubic III-V semiconductors. Anomalously low-pressure-induced softening of transverse acoustical (TA) phonon in indium antimonide suggests its much stronger anharmonicity comparing with similar binary tetrahedral semiconductors, for which quasiharmonic approximation is adequate. This unexpected behavior of InSb leads to significant deviation from the Weinstein model correlating the softening of TA phonons with the measured pressure of the fourfold to sixfold phase transition.image (c) 2024 WILEY-VCH GmbH