Structural study of FeP₂ at high pressure

Abstract

The structural stability of marcasite-type FeP₂ at high pressure has been studied by X-ray diffraction, Raman spectroscopy, and theoretical calculations. Experimental results show that no phase transitions happen up to 28 GPa at room temperature. The shortest axis of the marcasite-type FeP₂ cell, the c-axis, is the most compressible, due to the softening of edge-shared octahedra along the c-axis. The linear pressure coefficients and Grüneisen parameters of four Raman modes are determined. Theoretical calculations further support the experimental results and indicate that FeP₂ is still a semiconductor up to 35 GPa.

Keywords:

• marcasite-type structure
• high pressure
• theoretical calculations

Acknowledgements

The authors would like to thank A. Kurnosov for his assistance in Raman and XRD experiments. X. Wu is grateful for his Alexander von Humboldt Fellowship. S. Qin acknowledges the financial support of the National Natural Science Foundation of China (Grant no. 40672024).