Principles of spintronic THz emitters

TL;DR

This paper reviews the principles, physical effects, experimental techniques, fabrication methods, and recent advances in spintronic terahertz emitters, highlighting their potential in ultrafast spintronics applications.

Contribution

It provides a comprehensive background and overview of the physical mechanisms, experimental methods, and recent innovations in spintronic THz emitters, including novel material integrations.

Findings

Understanding of ultrafast spin interactions in solid-state materials.

Development of fabrication techniques for spintronic THz emitters.

Recent integration of topological insulators and antiferromagnets.

Abstract

Significant progress has been made in answering fundamental questions about how and, more importantly, on what time scales interactions between electrons, spins, and phonons occur in solid state materials. These complex interactions are leading to the first real applications of terahertz (THz) spintronics: THz emitters that can compete with traditional THz sources and provide additional functionalities enabled by the spin degree of freedom. This tutorial article is intended to provide the background necessary to understand, use, and improve THz spintronic emitters. A particular focus is the introduction of the physical effects that underlie the operation of spintronic THz emitters. These effects were, for the most part, first discovered through traditional spin-transport and spintronic studies. We therefore begin with a review of the historical background and current theoretical understanding of ultrafast spin physics that has been developed over the past twenty-five years. We then discuss standard experimental techniques for the characterization of spintronic THz emitters and - more broadly - ultrafast magnetic phenomena. We next present the principles and methods of the synthesis and fabrication of various types of spintronic THz emitters. Finally, we review recent developments in this exciting field including the integration of novel material platforms such as topological insulators as well as antiferromagnets and materials with unconventional spin textures.