Synchrotron x-ray diffraction and DFT study of non-centrosymmetric EuRhGe3 under high pressure

TL;DR

This study investigates the pressure-dependent structural behavior of EuRhGe3 using synchrotron x-ray diffraction and DFT calculations, revealing smooth compression without phase transition up to 35 GPa and deviations from theoretical predictions at high pressures.

Contribution

The paper provides the first detailed high-pressure structural analysis of EuRhGe3, combining experimental synchrotron data with DFT calculations to understand its compression behavior.

Findings

Unit cell volume contracts smoothly under pressure.

No structural transition observed up to 35 GPa.

Experimental volume data deviate from DFT predictions at high pressures.

Abstract

Antiferromagnetic intermetallic compound EuRhGe3 crystalizes in a non-centrosymmetric BaNiSn3-type (I4mm) structure. We studied its pressure-dependent crystal structure by using synchrotron powder x-ray diffraction at room temperature. Our results show a smooth contraction of the unit cell volume by applying pressure while preserving I4mm symmetry. No structural transition was observed up to 35 GPa. By the equation of state fitting analysis, the bulk modulus and its pressure derivative were determined to be 73 (1) GPa and 5.5 (2), respectively. Furthermore, similar to the isostructural EuCoGe3, an anisotropic compression of a and c lattice parameters was observed. Our experimental results show a good agreement with the pressure-dependent structural evolution expected from theoretical calculations below 13 GPa. Reflecting a strong deviation from integer Eu valence, the experimental volume data appear to be smaller than those of DFT calculated values at higher pressures.