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

Journal Article · Fri May 06 00:00:00 EDT 2016 · AIP Conference Proceedings

DOI:https://doi.org/10.1063/1.4946133· OSTI ID:22591266

Jena, Sushree Sangita, E-mail: [e-mail]; Rout, G. C., E-mail: [e-mail] ^[1]; Panda, S. K., E-mail: [e-mail]

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1. Physics Enclave, Plot No-664/4825, Lane-4A, Shree Vihar, Bhubaneswar-24, Odisha (India)

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.

• OSTI ID: 22591266
• Journal Information: AIP Conference Proceedings, Vol. 1728, 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); ISSN 0094-243X
• Country of Publication: United States
• Language: English

Related Subjects

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