Microscopic Route to Nematicity in Sr3Ru2O7

TL;DR

This paper investigates the microscopic origin of electronic nematicity in Sr3Ru2O7, proposing a tight-binding and extended Hubbard model to explain the Fermi surface distortion and its competition with ferromagnetism.

Contribution

It introduces a microscopic model based on t2g orbitals, spin-orbit coupling, and octahedral rotations to explain nematicity in Sr3Ru2O7, linking it to Fermi surface distortions and interactions.

Findings

Nematic phase driven by momentum-dependent quadrupole interactions.

Nematic state competes with ferromagnetic order but can pre-empt it.

Model aligns with angle-resolved photoemission data.

Abstract

An anisotropic metallic phase dubbed electronic nematic phase bounded by two consecutive metamagnetic transitions has been reported in the bilayer ruthenate Sr3Ru2O7. It has also been shown that the nematic and the accompanying metamagnetic transitions are driven by an effective momentum-dependent quadrupole-type interaction. Here, we study the microscopic origin of such an effective interaction. To elucidate the mechanism behind the spontaneous Fermi surface distortion associated with the nematic, we identify a simple tight binding model based on t2g orbitals, spin-orbit coupling and the rotation of RuO6 octahedra as starting point, consistent with the Fermi surface obtained from recent angle-resolved photoemission data. Within an extended Hubbard model the nematic state, characterized by an anisotropy between the bands near $(\pm \pi,0)$ and $(0,\pm \pi)$, then strongly competes with ferromagnetic order but pre-empts it via a finite nearest neighbor interaction. We discuss experimental means to confirm our proposal.