Volovik effect on NMR measurements of unconventional superconductors

Yunkyu Bang

doi:10.1103/PhysRevB.85.104524

← Back to search

Volovik effect on NMR measurements of unconventional superconductors

Yunkyu Bang

DOI 10.1103/PhysRevB.85.104524 · Physical Review B

T1

Active bibliographic source — not scientific approval

Bibliographic access preserves source history; it does not approve extracted materials or validate reported claims. Review warnings on each occurrence separately.

Abstract

We studied the Volovik effect (VE) on the NMR measurements of the two unconventional superconducting (SC) states: the d-wave and ±s-wave gap states. We derived the generic field dependencies of the spin-lattice relaxation rate 1/T1 and Knight shift K at the low-temperature limit of both SC states: 1/T1∝HlogH, K∝H for the d-wave state and 1/T1∝H, K∝H for the ±s-wave state. Performing numerical calculations, it is shown that (1) these generic power laws survive a realistic amount of impurities for a good part of low-field region and (2) the VE acts as an equivalent pair breaker to the unitary impurity scattering and hence induces the same temperature evolutions on 1/T1 and K as the unitary impurity does in both SC states. The latter finding implies that the VE should always be taken into account for the analysis of the NMR measurements in the mixed state.

Source-reported materials — not catalogue approval

Formula	Reported Tc (K)	Pressure (GPa)	Type
Ba0.69K0.31Fe2As2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown
BaFe2(As0.67P0.33)2 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula.	—	Pressure not reported	unknown