Spin contribution to the inverse Faraday effect of non-magnetic metals

TL;DR

This paper formulates the spin contribution to the inverse Faraday effect in non-magnetic metals, emphasizing the role of inversion symmetry, band degeneracies, and resonance features, supported by first-principles calculations.

Contribution

It introduces a formulation of the inverse Faraday effect that accounts for spin contributions and symmetry considerations, validated through analytical and numerical methods.

Findings

Spin component of the inverse Faraday effect in Au shows resonance features.

The formulation is invariant under unitary rotations within degenerate bands.

Resonance-like features in band structure significantly influence the effect.

Abstract

We formulate the spin contribution to the inverse Faraday effect of non-magnetic metals. We deal with the role of the inversion symmetry, which forces all electronic bands to be at least twice degenerate at every point in the Brillouin zone. We show both analytically and numerically that our formulation of the inverse Faraday effect is invariant under unitary rotation within the doubly degenerate set of bands. In addition, we show the importance of resonance-like features in the band structure for the inverse Faraday effect. Our first-principles computed spin component of the inverse Faraday effect in a simple metal such as Au is reminiscent of its optical absorption, with a characteristic d-s resonance in the optical spectrum.