Strain and vector magnetic field tuning of the anomalous phase in Sr 3 Ru 2 O 7

BRUIN, JAN A. N.; PERRY, ROBIN S.; BARBER, MARK E.; GRIGERA, SANTIAGO A.; HICKS, CLIFFORD W.; BRODSKY, DANIEL O.; BORZI, RODOLFO A.; MACKENZIE, ANDREW P.

Science Advances

AAAS

Año: 2017 vol. 3 p. 15018041 - 15018049

2375-2548

A major area of interest in condensed matter physics is the way electrons in correlated electron materials can self-organize into ordered states, and a particularly intriguing possibility is that they spontaneously choose apreferred direction of conduction. The correlated electron metal Sr 3 Ru 2 O 7 has an anomalous phase at low tem-peratures that features strong susceptibility toward anisotropic transport. This susceptibility has been thought toindicate a spontaneous anisotropy, that is, electronic order that spontaneously breaks the point-group symmetryof the lattice, allowing weak external stimuli to select the orientation of the anisotropy. We investigate further bystudying the response of Sr 3 Ru 2 O 7 in the region of phase formation to two fields that lift the native tetragonalsymmetry of the lattice: in-plane magnetic field and orthorhombic lattice distortion through uniaxial pressure. Theresponse to uniaxial pressure is surprisingly strong: Compressing the lattice by ~0.1% induces an approximately100% transport anisotropy. However, neither the in-plane field nor the pressure phase diagrams are qualitativelyconsistent with spontaneous symmetry reduction. Instead, both are consistent with a multicomponent orderparameter that is likely to preserve the point-group symmetry of the lattice, but is highly susceptible to perturbation.