Electrostatic Control of Magneto-Optic Excitonic Resonances in the van der Waals Ferromagnetic Semiconductor Cr$_2$Ge$_2$Te$_6$

Freddie Hendriks; Alexander N. Rudenko; Malte Roesner; Marcos H. D. Guimaraes

doi:10.1103/1fy4-4tyc

paper

Electrostatic Control of Magneto-Optic Excitonic Resonances in the van der Waals Ferromagnetic Semiconductor Cr $_{2}$ Ge $_{2}$ Te $_{6}$

arXiv:2408.09901 · doi:10.1103/1fy4-4tyc

Abstract

Two-dimensional magnetic materials exhibit strong magneto-optic effects and high tunability by electrostatic gating, making them very attractive for new magneto-photonic devices. Here, we characterize the magneto-optic Kerr effect (MOKE) spectrum of thin Cr $_{2}$ Ge $_{2}$ Te $_{6}$ from 1.13 to 2.67 eV, and demonstrate electrostatic control over of its magnetic and magneto-optic properties. The MOKE spectrum exhibits a strong feature around 1.43 eV which we attribute to a magnetic exchange-split excitonic state in Cr $_{2}$ Ge $_{2}$ Te $_{6}$ , in agreement with \textit{ab-initio} calculations. The gate dependence of the MOKE signals shows that the magneto-optical efficiency - rather than the saturation magnetization - is affected by electrostatic gating. We demonstrate a modulation of the magneto-optical strength by over 1 mdeg, with some wavelengths showing a modulation of 65% of the total magneto-optical signals, opening the door for efficient electrical control over light polarization through two-dimensional magnets. Our findings bring forward the fundamental understanding of magneto-optic processes in two-dimensional magnets and are highly relevant for the engineering of devices which exploit excitonic resonances for electrically-tunable magneto-photonic devices.

Electrostatic Control of Magneto-Optic Excitonic Resonances in the van der Waals Ferromagnetic Semiconductor Cr2​Ge2​Te6​

Abstract

References in corpus (11)

Electrostatic Control of Magneto-Optic Excitonic Resonances in the van der Waals Ferromagnetic Semiconductor Cr $_{2}$ Ge $_{2}$ Te $_{6}$