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arXiv · 1801.07129

Pressure induced BEC-BCS crossover in multi-band superconductors

D. Reyes·M. A. Continentino·F. Deus·C. Thomas
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Abstract

Superconductivity in strongly correlated systems is a remarkable phenomenon that attracts a huge interest. The study of this problem is relevant for materials as the high $T_c$ oxides, pnictides and heavy fermions. These systems also have in common the existence of electrons of several orbitals that coexist at a common Fermi-surface. In this paper we study the effect of pressure, chemical or applied on multi-band superconductivity. Pressure varies the atomic distances and consequently the overlap of the wave-functions in the crystal. This rearranges the electronic structure that we model including a pressure dependent hybridization between the bands. We consider the case of two-dimensional systems in a square lattice with inverted bands. We study the conditions for obtaining a pressure induced superconductor quantum critical point and show that hybridization, i.e., pressure can induce a BCS-BEC crossover in multi-band systems even for moderate interactions. We briefly discuss the influence of the symmetry of the order parameter in the results.

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D. Reyes, M. A. Continentino, F. Deus, C. Thomas. 2018-01-22. Pressure induced BEC-BCS crossover in multi-band superconductors. https://arxiv.org/abs/1801.07129

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