TITLE:
Theory of Electron Density of States of High Temperature Impurity Induced Anharmonic Superconductors
AUTHORS:
Hempal Singh, Anu Singh, Vinod Ashokan, B. D. Indu
KEYWORDS:
Dyson’s Equation; Lehman Representation; Anharmonicity
JOURNAL NAME:
Advances in Materials Physics and Chemistry,
Vol.2 No.4,
December
31,
2012
ABSTRACT: The expression for the
electron density of states (EDOS) of high temperature superconductors (HTS) has
been derived taking the disorder and anharmonicity effects as a central
problem. This has been dealt with the help of double time thermodynamic Green’s
function theory for electrons via a generalized Hamiltonian which consists of
the contribution due to 1) unperturbed electrons; 2) unperturbed
phonons; 3) isotopic impurities; 4) anharmonicities (no BCS type Hamiltonian
has been taken up in the formulation); and 5) electron-phonon interactions. The renormalization effects and emergence
of pairons appears as a unique feature of the theory and dependence of EDOS on
impurity concentration and temperature has been discussed in details with
special reference to the HTS.