Competition between Magnetic and Structural Transition in CrN

TL;DR

This paper investigates the interplay between magnetic and structural phase transitions in CrN, revealing that antiferromagnetic order and orthorhombic distortion coexist without opening an electronic gap, using first-principles calculations.

Contribution

It provides a detailed first-principles analysis of the magnetic and structural transition in CrN, identifying the most stable magnetic configuration and its electronic effects.

Findings

Antiferromagnetic order depletes states near Fermi level.

Structural distortion occurs simultaneously with magnetic ordering.

No electronic gap opens despite magnetic and structural changes.

Abstract

CrN is observed to undergo a paramagnetic to antiferromagnetic transition accompanied by a shear distortion from cubic NaCl-type to orthorhombic structure. Our first-principle plane wave and ultrasoft pseudopotential calculations confirm that the distorted antiferromagnetic phase with spin configuration arranged in double ferromagnetic sheets along [110] is the most stable. Antiferromagnetic ordering leads to a large depletion of states around Fermi level, but it does not open a gap. Simultaneous occurence of structural distortion and antiferromagnetic order is analyzed.