Asymmetric Berry-Phase Interference Patterns in a Single-Molecule Magnet

TL;DR

This study reveals asymmetric Berry-phase interference patterns in a Mn4 single-molecule magnet influenced by combined transverse and longitudinal magnetic fields, highlighting complex quantum tunneling behavior.

Contribution

It demonstrates the first observation of asymmetric Berry-phase interference patterns caused by noncollinear magnetoanisotropy in a single-molecule magnet.

Findings

Asymmetric interference patterns depend on the longitudinal field direction.

Reversal of the longitudinal field reflects the asymmetry about zero transverse field.

Berry-phase minima exhibit complex motion due to competing anisotropies.

Abstract

A Mn4 single-molecule magnet displays asymmetric Berry-phase interference patterns in the transverse-field (HT) dependence of the magnetization tunneling probability when a longitudinal field (HL) is present, contrary to symmetric patterns observed for HL=0. Reversal of HL results in a reflection of the transverse-field asymmetry about HT=0, as expected on the basis of the time-reversal invariance of the spin-orbit Hamiltonian which is responsible for the tunneling oscillations. A fascinating motion of Berry-phase minima within the transverse-field magnitude-direction phase space results from a competition between noncollinear magnetoanisotropy tensors at the two distinct Mn sites.