Asymmetric magnetic proximity interactions in MoSe${}_2$/CrBr${}_3$ van der Waals heterostructures

Abstract

Magnetic proximity interactions (MPIs) between atomically-thin semiconductors and two-dimensional magnets provide a means to manipulate spin and valley degrees of freedom in nonmagnetic monolayers, without the use of applied magnetic fields. In such van der Waals (vdW) heterostructures, MPIs originate in the nanometer-scale coupling between the spin-dependent electronic wavefunctions in the two materials, and typically their overall effect is regarded as an effective magnetic field acting on the semiconductor monolayer. Here we demonstrate that this picture, while appealing, is incomplete: The effects of MPIs in vdW heterostructures can be markedly asymmetric, in contrast to that from an applied magnetic field. Valley-resolved optical reflection spectroscopy of MoSe${}_2$/CrBr${}_3$ vdW structures reveals strikingly different energy shifts in the $K$ and $K^{\prime }$ valleys of the MoSe${}_2$, due to ferromagnetism in the CrBr${}_3$ layer. Strong asymmetry is observed at both the A- and B-exciton resonances. Density-functional calculations indicate that valley-asymmetric MPIs depend sensitively on the spin-dependent hybridization of overlapping bands, and as such are likely a general feature of such hybrid vdW structures. These studies suggest routes to selectively control \textit{specific} spin and valley states in monolayer semiconductors.

12 pages total (including 4 figures + 7 Supplemental Figures)

References in corpus (6)

• Magnetic 2D materials and heterostructures
• k.p theory for two-dimensional transition metal dichalcogenide semiconductors
• Evolution of interlayer and intralayer magnetism in three atomically thin chromium trihalides
• Layer-Resolved Magnetic Proximity Effect in van der Waals Heterostructures
• Magnetic Two-Dimensional Chromium Trihalides: A Theoretical Perspective
• Optical spectroscopy of excited exciton states in MoS2 monolayers in van der Waals heterostructures

Cited by in corpus (16)

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• Signatures of electric field and layer separation effects on the spin-valley physics of MoSe${}_2$/WSe${}_2$ heterobilayers: from energy bands to dipolar excitons
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• Enhanced Magnetization by Defect-Assisted Exciton Recombination in Atomically Thin CrCl${}_3$
• Tunable resonant s-p mixing of excitons in van der Waals heterostructures
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• Raman tensor for two-dimensional massive Dirac fermions
• Terahertz Spin-Light Coupling in Proximitized Dirac Materials
• Effect of spin-dependent tunneling and intervalley scattering in magnetic-semiconductor van der Waals heterostructures on exciton and trion polarization