Publications

Theory of strain-induced magnetic order and splitting of Tc and TTRSB in Sr2Ru O4

Rømer, A.T. and Kreisel, A. and Müller, M.A. and Hirschfeld, P.J. and Eremin, I.M. and Andersen, B.M.

PHYSICAL REVIEW B
Volume: 102 Pages:
DOI: 10.1103/PhysRevB.102.054506
Published: 2020

Abstract
The internal structure of the superconducting state in Sr2RuO4 remains elusive at present, and exhibits evidence for time-reversal symmetry breaking. Recent muon spin relaxation measurements under uniaxial strain have revealed an increasing splitting between the superconducting critical temperature Tc and the onset of time-reversal symmetry breaking TTRSB with applied strain (Grinenko et al., arXiv:2001.08152). In addition, static magnetic order is induced by the uniaxial strain beyond ∼1 GPa, indicating that unstrained Sr2RuO4 is close to a magnetic quantum critical point. Here we perform a theoretical study of the magnetic susceptibility and the associated pairing structure as a function of uniaxial strain. It is found that the recent muon relaxation data can be qualitatively explained from the perspective of spin-fluctuation mediated pairing and the associated strain dependence of accidentally degenerate pair states in unstrained Sr2RuO4. In addition, while unstrained Sr2RuO4 features mainly (2π/3,2π/3) magnetic fluctuations, uniaxial strain promotes (π,±π/2) magnetic order. © 2020 American Physical Society.

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