Pressure Induced Magnetic and Structural Transitions in Thmnasn: An Ab-Initio Study

Abstract

In this work, we present first principles density functional study of magnetism and electronic structures of ThMnAsN at ambient as well as at high pressure. Magnetic ground state of ThMnAsN as resulted from our calculations, is C-type anti-ferromagnet which is consistent with the experiments. Our results also suggest that C-AFM ground states of ThMnAsN is insulating in nature with a small energy gap $\sim0.4$ eV (using GGA exchange-correlation functional) at the Fermi level. Applying hydrostatic pressure in ThMnAsN, we find that all the structural parameters show anomalies at 9 GPa pressure which is attributed to a structural phase transition from tetragonal to collapse tetragonal phase. Apart from that our elastic constant and electronic structure calculations clearly show a increment in the metallic behaviour at higher pressure accompanying with a magnetic phase transition at the vicinity of 9 GPa pressure. We also observe that electronic structure of ThMnAsN at high pressure (9 GPa) closely resembles with the electronic structure of Fe-based superconductors.