Vibrational free energy and phase stability of paramagnetic and antiferromagnetic CrN from ab-initio molecular dynamics

Abstract

We present a theoretical first-principles method to calculate the free energy of a magnetic system in its high-temperature paramagnetic phase, including vibrational, electronic, and magnetic contributions. The method for calculating free energies is based on ab-initio molecular dynamics and combines a treatment of disordered magnetism using disordered local moments molecular dynamics (DLM-MD) with the temperature dependent effective potential (TDEP) method to obtain the vibrational contribution to the free energy. We illustrate the applicability of the method by obtaining the anharmonic free energy for the paramagnetic cubic and the antiferromagnetic orthorhombic phases of chromium nitride. The influence of lattice dynamics on the transition between the two phases is demonstrated by constructing the temperature-pressure phase diagram.

10 pages, 9 figures

References in corpus (3)

• Effect of magnetic disorder and strong electron correlations on the thermodynamics of CrN
• Evidence for a correlated insulator to antiferromagnetic metal transition in CrN
• Theory of the ferromagnetism in TiCrN solid solutions

Cited by in corpus (8)

• Structural stability and thermodynamics of CrN magnetic phases from ab initio and experiment
• Mode-decomposition based on crystallographic symmetry in the band-unfolding method
• Anomalous phonon lifetime shortening in paramagnetic CrN caused by magneto-lattice coupling: A combined spin and ab initio molecular dynamics study
• The role of N defects in paramagnetic CrN at finite temperatures from first-principles
• Lattice relaxations in disordered Fe-based materials in the paramagnetic state from first principles
• Temperature-dependent phonon spectra of magnetic random solid solutions
• Finite temperature elastic constants of paramagnetic materials within the disordered local moment picture from ab initio molecular dynamics calculations
• Semiclassical model of magnons in double-layered antiferromagnets