Theory of Electron Density of States of High Temperature Impurity Induced Anharmonic Superconductors

Abstract

<p class="MsoNormal"> <span lang="EN-US">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 </span><span lang="EN-US">1</span><span lang="EN-US">) unperturbed electrons</span><span lang="EN-US">;</span><span lang="EN-US"> </span><span lang="EN-US">2</span><span lang="EN-US">) unperturbed phonons</span><span lang="EN-US">;</span><span lang="EN-US"> </span><span lang="EN-US">3</span><span lang="EN-US">) isotopic impurities</span><span lang="EN-US">;</span><span lang="EN-US"> </span><span lang="EN-US">4</span><span lang="EN-US">) anharmonicities (no BCS type Hamiltonian has been taken up in the formulation)</span><span lang="EN-US">;</span><span lang="EN-US"> and </span><span lang="EN-US">5</span><span lang="EN-US">) 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.</span> </p> <p class="MsoNormal"> <span lang="EN-US"> </span> </p&gt