Thermal hall conductivity as a probe of gap structure in multiband superconductors: The case of Ba 1-xK xFe 2As 2

J. G. Checkelsky, R. Thomale, Lu Li, G. F. Chen, J. L. Luo, N. L. Wang, N. P. Ong

Research output: Contribution to journalArticle

14 Scopus citations

Abstract

The sign and profile of the thermal Hall conductivity κ xy gives important insights into the gap structure of multiband superconductors. With this perspective, we have investigated κ xy and the thermal conductivity κ xx in Ba 1-xK xFe 2As 2 which display large peak anomalies in the superconducting state. The anomalies imply that a large holelike quasiparticle (QP) population exists below the critical temperature T c. We show that the QP mean free path inferred from κ xx reproduces the observed anomaly in κ xy, providing a consistent estimate of a large QP population. Further, we demonstrate that the peak structure and holelike signal are consistent with a theoretical scenario where, despite potentially large gap variations on the electron pockets, the minimal homogeneous gap of the superconducting phase resides at a hole pocket. Implications for probing the gap structure in the broader class of pnictide superconductors are discussed.

Original languageEnglish (US)
Article number180502
JournalPhysical Review B - Condensed Matter and Materials Physics
Volume86
Issue number18
DOIs
StatePublished - Nov 6 2012

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics

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