Spin Quenching Assisted by a Strongly Anisotropic Compression Behavior in MnP

TL;DR

This study investigates how high pressure causes anisotropic compression in MnP, leading to spin quenching and influencing its magnetic and superconducting properties, with insights from experiments and first-principles calculations.

Contribution

It reveals the role of anisotropic compression in spin quenching and its impact on electronic structure and superconductivity in MnP, a novel insight into pressure-induced magnetic transitions.

Findings

MnP exhibits strong anisotropic compressibility along the b axis.

Pressure induces spin quenching, reducing magnetic order.

Superconductivity emerges around 8 GPa after spin quenching.

Abstract

We studied the crystal structure and spin state of MnP under high pressure with synchrotron X-ray diffraction and X-ray emission spectroscopy. MnP has an exceedingly strong anisotropy in compressibility, with the primary compressible direction along the b axis of the Pnma structure. X-ray emission spectroscopy reveals a pressure-driven quenching of the spin state in MnP. Firstprinciples calculations suggest that the strongly anisotropic compression behavior significantly enhances the dispersion of the Mn d-orbitals and the splitting of the d orbital levels compared to the hypothetical isotropic compression behavior. Thus, we propose spin quenching results mainly from the significant enhancement of the itinerancy of d electrons and partly from spin rearrangement occurring in the split d-orbital levels near the Fermi level. This explains the fast suppression of magnetic ordering in MnP under high pressure. The spin quenching lags behind the occurrence of superconductivity at ~8 GPa implying that spin fluctuations govern the electron pairing for superconductivity.