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arXiv · 2402.19040

Pressure-induced optical anisotropy of HfS$_2$

Igor Antoniazzi·Tomasz Woźniak·Amit Pawbake·Natalia Zawadzka·Magdalena Grzeszczyk·Zahir Muhammad·Weisheng Zhao·Jordi Ibáñez·Clement Faugeras·Maciej R. Molas·Adam Babiński
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Abstract

The effect of pressure on Raman scattering (RS) in the bulk HfS$_2$ is investigated under hydrostatic and non-hydrostatic conditions. The RS lineshape does not change significantly in the hydrostatic regime, showing a systematic blueshift of the spectral features. In a non-hydrostatic environment, seven peaks emerge in the spectrum ($P$=7 GPa) dominating the lineshape up to $P$=10.5 GPa. The change in the RS lineshape manifests a pressure-induced phase transition in HfS$_2$. The simultaneous observation of both low-pressure (LP) and high-pressure (HP) related RS peaks suggests the corresponding coexistence of two different phases over a large pressure range. We found that the HP-related phase is metastable, persisting during the decompression cycle down to $P$=1.2 GPa with the LP-related features finally recovering at even lower pressures. The angle-resolved polarized RS (ARPRS) performed under $P$=7.4 GPa revealed a strong in-plane anisotropy of both the LP-related A$_{1g}$ mode and the HP peaks. The anisotropy is related to the possible distortion of the structure induced by the non-hydrostatic component of the pressure. We describe the obtained results by the influence of the non-hydrostatic pressure on the observed phase transition. We interpret our results in terms of a distorted $Pnma$ phase as a possible HP induced structure of HfS$_2$.

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Igor Antoniazzi, Tomasz Woźniak, Amit Pawbake, Natalia Zawadzka, Magdalena Grzeszczyk, Zahir Muhammad, Weisheng Zhao, Jordi Ibáñez, Clement Faugeras, Maciej R. Molas, Adam Babiński. 2024-02-29. Pressure-induced optical anisotropy of HfS$_2$. https://doi.org/10.1063/5.0205909

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