Supersymmetric spin-phonon coupling prevents odd integer spins from quantum tunneling

TL;DR

This paper reveals that supersymmetry in spin-phonon systems can inhibit quantum tunneling of magnetization in integer spin systems, challenging previous assumptions about phonon-induced tunneling.

Contribution

It uncovers a supersymmetric mechanism that prevents tunneling gaps in certain spin-phonon Hamiltonians, offering new insights into spin system stability.

Findings

Supersymmetry involves both spin and phonon degrees of freedom.

Certain spin-phonon Hamiltonians are resistant to tunneling gap formation.

Supersymmetry explains robustness against quantum tunneling in integer spins.

Abstract

Quantum tunneling of the magnetization is a phenomenon that impedes the use of small anisotropic spin systems for storage purposes even at the lowest temperatures. Phonons, usually considered for temperature dependent relaxation of magnetization over the anisotropy barrier, also contribute to magnetization tunneling for integer spin quantum numbers. Here we demonstrate that certain spin-phonon Hamiltonians are unexpectedly robust against the opening of a tunneling gap, even for strong spin-phonon coupling. The key to understanding this phenomenon is provided by an underlying supersymmetry that involves both spin and phonon degrees of freedom.