Universität zu Köln

Piazza, Francesco ORCID: 0000-0003-1332-6627, Zwerger, Wilhelm and Strack, Philipp ORCID: 0000-0002-7040-521X (2016). FFLO strange metal and quantum criticality in two dimensions: Theory and application to organic superconductors. Phys. Rev. B, 93 (8). COLLEGE PK: AMER PHYSICAL SOC. ISSN 2469-9969

Full text not available from this repository.

Abstract

Increasing the spin imbalance in superconductors can spatially modulate the gap by forming Cooper pairs with finite momentum. For large imbalances compared to the Fermi energy, the inhomogeneous FFLO superconductor ultimately becomes a normal metal. There is mounting experimental evidence for this scenario in two-dimensional (2D) organic superconductors in large in-planemagnetic fields; this is complemented by ongoing efforts to realize this scenario in coupled tubes of atomic Fermi gases with spin imbalance. Yet, a theory for the phase transition from a metal to an FFLO superconductor has not been developed so far and the universality class has remained unknown. Here we propose and analyze a spin imbalance driven quantum critical point between a 2D metal and an FFLO phase in anisotropic electron systems. We derive the effective action for electrons and bosonic FFLO pairs at this quantum phase transition. Using this action, we predict non-Fermi-liquid behavior and the absence of quasiparticles at a discrete set of hot spots on the Fermi surfaces. This results in strange power laws in thermodynamics and response functions, which are testable with existing experimental setups on 2D organic superconductors and may also serve as signatures of the elusive FFLO phase itself. The proposed universality class is distinct from previously known quantum critical metals and, because its critical fluctuations appear already in the pairing channel, a promising candidate for naked metallic quantum criticality over extended temperature ranges.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Piazza, Francesco UNSPECIFIED orcid.org/0000-0003-1332-6627 UNSPECIFIED Zwerger, Wilhelm UNSPECIFIED UNSPECIFIED UNSPECIFIED Strack, Philipp UNSPECIFIED orcid.org/0000-0002-7040-521X UNSPECIFIED
URN:	urn:nbn:de:hbz:38-284730
DOI:	10.1103/PhysRevB.93.085112
Journal or Publication Title:	Phys. Rev. B
Volume:	93
Number:	8
Date:	2016
Publisher:	AMER PHYSICAL SOC
Place of Publication:	COLLEGE PK
ISSN:	2469-9969
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language SPIN-FERMION MODEL; CRITICAL FIELD; STATE; PHASE Multiple languages Materials Science, Multidisciplinary; Physics, Applied; Physics, Condensed Matter Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/28473