Metallic quantum critical points with finite BCS couplings

• Autores: Raghu, S.; Torroba, Gonzalo; Wang, Huajia
• Año de publicación: 2015
• Idioma: inglés
• Tipo de recurso: artículo
• Materia: Quantum Criticality; Superconductivity; Non-Fermi Liquid
• Institución: Consejo Nacional de Investigaciones Científicas y Técnicas

We study the fate of superconductivity in the vicinity of a class of metallic quantum critical points obtained by coupling a Fermi surface to a critical boson. In such systems there is a competition between the enhanced pairing tendency due to the presence of long-range attractive interactions near criticality, and the suppression of superconductivity due to the destruction of the Landau quasiparticles. We show that there are regimes in which these two effects offset one another, resulting in a non-Fermi liquid fixed point with finite, scale invariant, BCS coupling. While these interactions lead to substantial superconducting fluctuations, they do not drive the system into a superconducting ground state. The metallic quantum critical fixed points are connected to the superconducting regime by a continuous phase transition. These results are established using a controlled expansion in the deviation from d=3 spatial dimensions, as well as in a large number N of internal flavors. We discuss the possible relevance of our findings to the phenomenon of superconducting domes condensing out of a non-Fermi liquid normal state near quantum critical points.
Fil: Raghu, S.. University of Stanford. Physics Department; Estados Unidos. Slac National Accelerator Laboratory; Estados Unidos
Fil: Torroba, Gonzalo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte; Argentina. Comisión Nacional de Energía Atómica. Gerencia del Area Investigación y Aplicaciones No Nucleares. Gerencia de Física (Centro Atómico Bariloche). Grupo de Partículas y Campos; Argentina
Fil: Wang, Huajia. University of Stanford. Physics Department; Estados Unidos