Two-band model for high-temperature superconductivity

Theoretical Study of Specific Heat and Density of States of MgB<sub>2</sub> Superconductor in Two Band Model

“…For MgB 2 , an approach of such kind is also directly proposed by the nature of the electron spectrum mentioned. There is a number of two band type approaches for superconductivity in MgB 2 [16]. We may note that two band models have been exploited in various realizations for high-T c cuprate superconductivity [16,17].…”

Shape Resonance at a Lifshitz Transition for High Temperature Superconductivity in Multiband Superconductors

“…[32] Several practical realizations of the material design protocol [17,18] for high temperature superconductivity tuned at a shape resonance have been reported for superlattices of superconducting layers made of:…”

Effective Ginzburg–Landau free energy functional for multi-band isotropic superconductors

“…Phase relations (8) must be satisfied over the entire volume of a superconductor: ϕ 1 (r) − ϕ 2 (r) = const, otherwise superconducting state will be destroyed -Eqs. (1,2). Hence the phases must change equally:…”

“…One of the main feature of these materials is the presence of two energy gaps ∆ 1 and ∆ 2 which, however, vanishes at the same temperature T c (Fig.1). According to microscopic theory [1][2][3][4] presence of the two gaps is explained by the fact that in each band i an own coupling constant g ii existsthe intraband constant. In the same time, the interband coupling constant g ij exists too, which, on the one hand, enhances pairing of electrons, on the other hand, leads to the single critical temperature T c .…”

“…In the same time, the interband coupling constant g ij exists too, which, on the one hand, enhances pairing of electrons, on the other hand, leads to the single critical temperature T c . BCS gap equations for a two-band superconductor are [1][2][3]:…”