# Anomalous spin precession under a geometrical torque

## TL;DR

This paper reveals an anomalous spin precession phenomenon caused by a geometrical torque related to Berry curvature, leading to precession frequencies exceeding the Larmor frequency or inverted orientations.

## Contribution

It introduces the concept of a geometrical torque affecting spin precession, a novel insight into spin dynamics influenced by Berry curvature.

## Key findings

- Identification of anomalous precession with higher-than-Larmor frequency
- Demonstration of inverted spin orientation due to geometrical effects
- Linking the effect to a finite spin Berry curvature

## Abstract

Precession and relaxation predominantly characterize the real-time dynamics of a spin driven by a magnetic field and coupled to a large Fermi sea of conduction electrons. We demonstrate an anomalous precession with frequency higher than the Larmor frequency or with inverted orientation in the limit where the electronic motion adiabatically follows the spin dynamics. For a classical spin, the effect is traced back to a geometrical torque resulting from a finite spin Berry curvature.