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Title: Theoretical study of orbital ordering induced structural phase transition in iron pnictides

Abstract

We attribute the structural phase transition (SPT) in the parent compounds of the iron pnictides to orbital ordering. Due to anisotropy of the d{sub xz} and d{sub yz} orbitals in the xy plane, orbital ordering makes the orthorhombic structure more favorable and thus inducing the SPT. We consider a one band model Hamiltonian consisting of first and second-nearest-neighbor hopping of the electrons. We introduce Jahn-Tellar (JT) distortion in the system arising due to the orbital ordering present in this system. We calculate the electron Green’s function by using Zuvareb’s Green’s function technique and hence calculate an expression for the temperature dependent lattice strain which is computed numerically and self-consistently. The temperature dependent electron specific heat is calculated by minimizing the free energy of the system. The lattice strain is studied by varying the JT coupling and elastic constant of the system. The structural anomaly is studied through the electron occupation number and the specific heat by varying the physical parameters like JT coupling, lattice constant, chemical potential and hopping integrals of the system.

Authors:
;  [1];
  1. Physics Enclave, Plot No-664/4825, Lane-4A, Shree Vihar, Bhubaneswar-24, Odisha (India)
Publication Date:
OSTI Identifier:
22591266
Resource Type:
Journal Article
Journal Name:
AIP Conference Proceedings
Additional Journal Information:
Journal Volume: 1728; Journal Issue: 1; Conference: ICC 2015: International conference on condensed matter and applied physics, Bikaner (India), 30-31 Oct 2015; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0094-243X
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ANISOTROPY; COUPLING; ELASTICITY; ELECTRONS; FREE ENERGY; GREEN FUNCTION; HAMILTONIANS; IRON COMPOUNDS; JAHN-TELLER EFFECT; LATTICE PARAMETERS; OCCUPATION NUMBER; ORTHORHOMBIC LATTICES; PHASE TRANSFORMATIONS; PNICTIDES; POTENTIALS; SPECIFIC HEAT; STRAINS; TEMPERATURE DEPENDENCE

Citation Formats

Jena, Sushree Sangita, E-mail: sushree@iopb.res.in, Rout, G. C., E-mail: gcr@iopb.res.in, and Panda, S. K., E-mail: skp@iopb.res.in. Theoretical study of orbital ordering induced structural phase transition in iron pnictides. United States: N. p., 2016. Web. doi:10.1063/1.4946133.
Jena, Sushree Sangita, E-mail: sushree@iopb.res.in, Rout, G. C., E-mail: gcr@iopb.res.in, & Panda, S. K., E-mail: skp@iopb.res.in. Theoretical study of orbital ordering induced structural phase transition in iron pnictides. United States. doi:10.1063/1.4946133.
Jena, Sushree Sangita, E-mail: sushree@iopb.res.in, Rout, G. C., E-mail: gcr@iopb.res.in, and Panda, S. K., E-mail: skp@iopb.res.in. Fri . "Theoretical study of orbital ordering induced structural phase transition in iron pnictides". United States. doi:10.1063/1.4946133.
@article{osti_22591266,
title = {Theoretical study of orbital ordering induced structural phase transition in iron pnictides},
author = {Jena, Sushree Sangita, E-mail: sushree@iopb.res.in and Rout, G. C., E-mail: gcr@iopb.res.in and Panda, S. K., E-mail: skp@iopb.res.in},
abstractNote = {We attribute the structural phase transition (SPT) in the parent compounds of the iron pnictides to orbital ordering. Due to anisotropy of the d{sub xz} and d{sub yz} orbitals in the xy plane, orbital ordering makes the orthorhombic structure more favorable and thus inducing the SPT. We consider a one band model Hamiltonian consisting of first and second-nearest-neighbor hopping of the electrons. We introduce Jahn-Tellar (JT) distortion in the system arising due to the orbital ordering present in this system. We calculate the electron Green’s function by using Zuvareb’s Green’s function technique and hence calculate an expression for the temperature dependent lattice strain which is computed numerically and self-consistently. The temperature dependent electron specific heat is calculated by minimizing the free energy of the system. The lattice strain is studied by varying the JT coupling and elastic constant of the system. The structural anomaly is studied through the electron occupation number and the specific heat by varying the physical parameters like JT coupling, lattice constant, chemical potential and hopping integrals of the system.},
doi = {10.1063/1.4946133},
journal = {AIP Conference Proceedings},
issn = {0094-243X},
number = 1,
volume = 1728,
place = {United States},
year = {2016},
month = {5}
}