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arXiv · 2503.11971

Soft mode induced structural phase transition in Ba$_2$ZnTeO$_6$ at high pressure

Bidisha Mukherjee·Surajit Adhikari·Mrinmay Sahu·Asish Kumar Mishra·Bhagyashri Giri·Priya Johari·Konstantin Glazyrin·Goutam Dev Mukherjee
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Abstract

In this paper, we present a thorough investigation of vibrational, structural, and electronic properties of perovskite-type rhombohedral Ba$_2$ZnTeO$_6$ (BZTO) under systematic application of pressure. To carry out the analysis, we have performed pressure-dependent Raman spectroscopic measurements, synchrotron XRD, and density functional theory-based calculations. At ambient conditions, BZTO stabilizes in $R\bar{3}m$ space group, which under pressure undergoes a structural transition to a monoclinic phase with space group $C2/m$ at around 18~GPa. In-depth Raman analysis reveals softening of a phonon mode E$_g$ ($\sim $ 28cm$^{-1}$) leads to the structural phase transition. First principle DFT calculations also indicate that the doubly degenerate soft mode associated with the in-phase TeO$_6$ octahedral rotation drives the structure to a lower symmetry phase $C2/m$.

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Bidisha Mukherjee, Surajit Adhikari, Mrinmay Sahu, Asish Kumar Mishra, Bhagyashri Giri, Priya Johari, Konstantin Glazyrin, Goutam Dev Mukherjee. 2025-03-15. Soft mode induced structural phase transition in Ba$_2$ZnTeO$_6$ at high pressure. https://arxiv.org/abs/2503.11971

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