Evolution of the Andreev bands in the half-filled superconducting periodic Anderson model

Abstract

We employ the periodic Anderson model with superconducting correlations in the conduction band at half filling to study the behavior of the in-gap bands in a heterostructure consisting of a molecular layer deposited on the surface of a conventional superconductor. We use the dynamical mean-field theory to map the lattice model on the superconducting single impurity model with self-consistently determined bath and use the continuous-time hybridization expansion (CT-HYB) quantum Monte Carlo and the iterative perturbation theory (IPT) as solvers for the impurity problem. We present phase diagrams for square and triangular lattice that both show two superconducting phases that differ by the sign of the induced pairing, in analogy to the $0$ and $\pi$ phases of the superconducting single impurity Anderson model and discuss the evolution of the spectral function in the vicinity of the transition. We also discuss the failure of the IPT for superconducting models with spinful ground state and the behavior of the average expansion order of the CT-HYB simulation.