Theory of Spin Resonance Spectroscopy in an Electron Microscope

Abstract

Coherent spin resonance methods, such as nuclear magnetic resonance and electron spin resonance spectroscopy, have led to spectrally highly sensitive, non-invasive quantum imaging techniques. In this talk, I will present joint theoretical work with my collaborators* on a pump- probe spin resonance spectroscopy approach, designed for electron microscopy, based on microwave pump fields and electron probes [1]. Starting from the description of the coupling of free-electrons and localized sample spins, I will introduce the general method and discuss the size of the effect, in particular, the phase shift on the electron wave function and the corresponding deflection angle. I will also present a framework for the simulation of spin resonance spectroscopy in Transmission Electron Microscopy (TEM) that we have recently developed [2] and discuss our results on the quantum metrological precision limits associated with the technique and the optimal measurement strategy [3]. Notably, state-of-the-art TEM provides the means to detect signals almost as small as that due to a single electron spin in principle. This could enable state-selective observation of spin dynamics on the nanoscale.