Martensitic phase transition from cubic to tetragonal V3Si: an electronic structure study
Departamento de Física, Universidade Federal de Santa Catarina, 88040-900 Florianópolis, SC, Brazil
Corresponding author: a firstname.lastname@example.org
Revised: 23 September 2008
Published online: 29 November 2008
In this study we focus on the subtle changes which occur in the electronic structure and in the Fermi surface topology with the low temperature (21.3 K) cubic → tetragonal martensitic phase transition in V3Si. From the calculations it has been verified the occurrence of a charge transfer from V atoms to Si atoms, with the phase transition to a tetragonal variant of the A-15 structure. The orbital population of s- and p-states of V atoms in the 2e and 4k sites of the tetragonal phase are practically the same. Major differences are seen in the occupation of d-states. There is a decrease in the average electronic energy with the structural transition, which occurs as a result of the emptying of V d-states (mostly from bands 19–20), and these electrons enter preferentially into the Si p-orbitals. The present results thus indicate that the electronic features of the martensitic transition of V3Si, besides being intimately related to the splitting of the Γ12 into the Γ1+ and Γ3+ states and the position of the Γ1+ state relatively to EF, is mainly associated with the gain in the average electronic energy which occurs from an electron transfer from V-d → Si-p states. This is the main source to explain the stability of the tetragonal phase formed at low temperature in this system.
PACS: 71.15.Ap – Basis sets (LCAO, plane-wave, APW, etc.) and related methodology (scattering methods, ASA, linearized methods, etc.) / 71.20.Lp – Intermetallic compounds / 74.25.Jb – Electronic structure / 74.70.Ad – Metals; alloys and binary compounds
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag, 2008