Fingerprints of collective magnetic excitations in inelastic electron tunneling spectroscopy

TL;DR

This paper introduces a method to measure local spin density of states in magnetic systems using inelastic electron tunneling spectroscopy, enabling analysis of larger systems and zero-frequency modes.

Contribution

It demonstrates that double differential conductance can reveal local spin density of states, extending the capability beyond small systems and elastic measurements.

Findings

Double differential conductance measures local spin density of states.

Method applicable to large systems and zero-frequency modes.

Studied tunneling currents of spin-1/2 and -1 Heisenberg chains.

Abstract

Spin-flip inelastic electron tunneling spectroscopy allows magnetic materials to be probed at the single-atom level via scanning tunneling microscopy. Previously, the local spectral weight of spin excitations of small systems has been deduced from discrete steps in the differential conductance. However, this is not viable for large systems. We show that the local spin density of states can be measured via the double differential conductance. This contrasts with elastic measurements where the local density of electronic states is deduced from the differential conductance. We study the tunneling currents of the spin-1/2 and -1 Heisenberg chains and propose a method to probe zero-frequency modes.