Three-band intrinsic Kerr effect in Sr2RuO4

Martin Gradhand, James F Annett, Karol I. Wysokinski

Research output: Contribution to journalArticle (Academic Journal)peer-review

Abstract

The Kerr effect in the chiral triplet superconductor Sr2RuO4 has proved difficult to explain unless either impurity scattering or multiband superconductivity is included in the theory. In this paper, we concentrate on the analysis of the ac Hall conductivity and the Kerr signal in terms of a realistic three-dimensional three-band model of the Fermi surface. We consider two possible unique observable signatures which could be used to distinguish the three-band model from other possible sources of the Kerr signal. Firstly, we consider in detail the temperature dependence of the Kerr signal. For most frequencies, this varies with temperature as near to Tc while for others, Hebel-Slichter-like enhancement or decrease below Tc are observed. In contrast, the sum-rule integral over all frequencies is monotonic and follows the temperature dependence of . Secondly, we examine the Kerr effect in the presence of a c-axis magnetic field. There is some evidence that in a small c-axis field the order parameter transforms from chiral to a non-chiral ground state. We show that in the non-chiral state, both spin – orbit coupling and a finite B field are necessary for the appearance of a non-zero Hall conductivity and Kerr effect. The transition from chiral to non-chiral pairing state would lead to an observable dramatic change in Kerr signal at some critical magnetic field.

Original languageEnglish
Pages (from-to)525-537
Number of pages13
JournalPhilosophical Magazine
Volume95
Issue number5-6
Early online date3 Dec 2014
DOIs
Publication statusPublished - 11 Feb 2015

Keywords

  • spin triplet superconductor, strontium ruthenate, Kerr effect, chiral state

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