Open AccessEvidence of ferromagnetic ground state and strong spin phonon coupling in Zr2TiAl with bi-axial strain: first principles study
Author(s) -
P. Venugopal Reddy,
Seung Cheol Lee,
Satadeep Bhattacharjee
Publication year - 2019
Publication title -
journal of physics communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.407
H-Index - 17
ISSN - 2399-6528
DOI - 10.1088/2399-6528/ab1cd8
Subject(s) - condensed matter physics , tetragonal crystal system , ferromagnetism , phonon , materials science , ground state , fermi level , electronic structure , phase (matter) , physics , electron , atomic physics , quantum mechanics
A detailed study on the inter-metallic alloy, Zr 2 TiAl, has been carried out using first principle electronic structure calculations. We found that a small value of bi-axial strain/stress cause a phase change from anti-ferromagnetic(AFM) to ferromagnetic(FM) with a structural transition from face center cubic (fcc) to body center tetragonal (bct). Calculated electronic band structures show that all strained structures are metallic in nature with Zr- d and Ti- d orbital dominated energy bands near the Fermi level(E F ). The stability of FM phase is confirmed with phonon dispersion calculations by using density functional perturbation theory (DFPT). It has been observed that AFM state with both positive and negative bi-axial stress exhibits unstable modes while corresponding FM state shows no such instability. This clearly indicates the existence of large spin phonon coupling in this material.