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

• DOI: 10.1007/s10948-010-1096-y
• Publication Date: 2010-12-29T04:35:54Z
• Authors: Davide Innocenti; Antonio Valletta; Antonio Bianconi
• Keywords: Bose-BCS crossover; Multiband superconductivity; Condensed Matter - Superconductivity; FOS: Physical sciences; Bipolarons; 7. Clean energy; 01 natural sciences; bipolarons; bose-bcs crossover; lifshitz transition; multiband superconductivity; shape resonance; Lifshitz transition; Shape resonance; Superconductivity (cond-mat.supr-con); 0103 physical sciences

20 pages, 3 figures, proceedings of the "Superstripes 2010" Conference Erice, July 19 to 25, 2010 Italy<br/>We discuss the shape resonance in the superconducting gaps of a two band superconductor by tuning the chemical potential at a Lifshitz transition for Femi surface neck collapsing and for spot appearing. The high temperature superconducting scenario for complex matter shows the coexistence of a first BCS condensate made of Cooper pairs in the first band and a second boson-like condensate made of bosons like bipolarons, in the second band where the chemical potential is tuned near a Lifshitz transition. The interband coupling controls the shape resonance in the pair exchange between the two condensates. We discuss the particular BCS-Bose crossover that occurs at the shape resonance tuning the Lifshitz parameter (the energy difference between the chemical potential and the Lifshitz topological transition) like tuning the external magnetic field for the Feshbach resonances in ultracold gases. This superconducting phase provides a particular case of topological superconductivity with multiple condensates of different winding numbers<br/>