THz electric field control of spins in collinear antiferromagnet Cr$_{2}$O$_{3}$

TL;DR

This paper demonstrates that THz electric fields can control spins in collinear antiferromagnet Cr₂O₃, revealing a new mechanism for ultrafast and energy-efficient spin manipulation without electromagnons.

Contribution

It shows that THz electric fields can excite spin resonance in Cr₂O₃ without electromagnons, with effects comparable to magnetic excitation, highlighting a novel control mechanism for antiferromagnetic spin dynamics.

Findings

THz electric fields can excite spin resonance in Cr₂O₃.

Electric and magnetic fields produce comparable effects on spins.

The effects depend on the orientation of the electric field and Néel vector.

Abstract

The idea to find a magnet that responds to an electric field as efficiently as to its magnetic counterpart has long intrigued people's minds and recently became a cornerstone for future energy efficient and nano-scalable technologies for magnetic writing and information processing. In contrast to electric currents, a control by electric fields promises much lower dissipations and in contrast to magnetic fields, electric fields are easier to apply to a nanoscale bit. Recently, the idea to find materials and mechanisms facilitating a strong and simultaneously fast response of spins to electric field has fueled an intense research interest to electromagnons in non-collinear antiferromagnets. Here we show that THz spin resonance at the frequency 0.165 THz in collinear antiferromagnet Cr$_{2}$O$_{3}$, which does not host any electromagnons, can be excited by both THz magnetic and electric fields. The mechanisms result in comparable effects on spin dynamics, when excited by freely propagating electromagnetic wave, but have different dependencies on the orientation of the applied THz electric field and the antiferromagnetic N\'eel vector. Hence this discovery opens up new chapters in the research areas targeting to reveal novel principles for the fastest and energy efficient information processing - ultrafast magnetism, antiferromagnetic spintronics, and THz magnonics.