Order-parameter symmetry and mode-coupling effects at dirty superconducting quantum phase transitions

Rastko Sknepnek; Thomas Vojta; Rajesh Narayanan

doi:10.1103/PhysRevB.70.104514

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Order-parameter symmetry and mode-coupling effects at dirty superconducting quantum phase transitions

Rastko Sknepnek, Thomas Vojta, Rajesh Narayanan

DOI 10.1103/PhysRevB.70.104514 · Physical Review B

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Abstract

We derive an order-parameter field theory for a quantum phase transition between a disordered metal and an exotic (non-s-wave) superconductor. Mode coupling effects between the order parameter and other fermionic soft modes lead to an effective long-range interaction between the anomalous density fluctuations which is reflected in singularities in the free energy functional. However, this long-range interaction is not strong enough to suppress disorder fluctuations. The asymptotic critical region is characterized by run-away flow to large disorder. For weak coupling, this asymptotic region is very narrow. It is preempted by a wide crossover regime with mean-field critical behavior and, in the p-wave case, logarithmic corrections to scaling in all dimensions.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
UGe2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	1	Pressure not reported	onset
ZrZn2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	1	Pressure not reported	onset