Josephson lattice model for phase fluctuations of local pairs in copper oxide superconductors

Abstract

We derive an expression for the effective Josephson coupling from the microscopic Hubbard model. It serves as a starting point for the description of phase fluctuations of local Cooper pairs in d x 2 −y 2wave superconductors in the framework of an effective XY model of plaquettes, the Josephson lattice. The expression for the effective interaction is derived by means of the local-force theorem, and it depends on local symmetry-broken correlation functions that we obtain using the cluster dynamical mean-field theory. Moreover, we apply the continuum limit to the Josephson lattice to obtain an expression for the gradient term in the Ginzburg-Landau theory and compare predicted London penetration depths and Kosterlitz-Thouless transition temperatures with experimental data for YBa2Cu3O7−x . arXiv:1810.12986v2 [cond-mat.str-el]

Multi-band D-TRILEX approach to materials with strong electronic correlations

“…To this aim one can either consider a suitable reference problem related to the desired superconducting order parameter (see, e.g., Refs. [56,131,158,159]) and use the D-TRILEX form for the polarization operator in the particle-particle channel, or to additionally account for the scattering on the transverse momentum-and frequency-dependent bosonic fluctuations in the polarization operator in the particle-particle channel in the case of a single-site reference system [91,160,161]. Going inside the superconducting phase would require to introduce an anomalous component of the Green's function working in the Nambu space formalism similarly to what has been proposed in the framework of the TRILEX approach [91].…”

Dynamical control of the conductivity of an atomic Josephson junction

“…Based on microscopic models, various mechanisms have been proposed such as enhancement of electron-phonon coupling [8][9][10][11][12], control of competing order [13][14][15][16][17][18], photoinduced η-pairing [19][20][21] and cooling in multi-band systems [22,23]. Meanwhile, phenomenological approaches have been used to understand the effect of superconducting fluctuations in photo-excited systems [24][25][26][27][28][29][30][31][32]. In Refs.…”