Strong manipulation of the valley splitting upon twisting and gating in MoSe${}_2$/CrI${}_3$ and WSe${}_2$/CrI${}_3$ van der Waals heterostructures

Abstract

We investigate the twist-angle and gate dependence of the proximity-induced exchange coupling in the monolayer transition-metal dichalcogenides (TMDCs) MoSe${}_2$ and WSe${}_2$ due to the vdW coupling to the ferromagnetic semiconductor CrI${}_3$, from first-principles calculations. A model Hamiltonian, that captures the relevant band edges at the $K/K^{\prime }$ valleys of the proximitized TMDCs, is employed to quantify the proximity-induced exchange. Upon twisting from 0° to 30°, we find a transition of the TMDC valence band (VB) edge exchange splitting from about $-2$ to $2$ meV, while the conduction band (CB) edge exchange splitting remains nearly unchanged at around $-3$ meV. For the VB of WSe${}_2$ (MoSe${}_2$) on CrI${}_3$, the exchange coupling changes sign at around 8° (16°). We find that even at the angles with almost zero spin splittings of the VB, the real-space spin polarization profile of holes at the band edge is highly non-uniform, with alternating spin up and spin down orbitals. Furthermore, a giant tunability of the proximity-induced exchange coupling is provided by a transverse electric field of a few V/nm. We complement our \textit{ab initio} results by calculating the excitonic valley splitting to provide experimentally verifiable optical signatures of the proximity exchange. Specifically, we predict that the valley splitting increases almost linearly as a function of the twist angle. Furthermore, the proximity exchange is highly tunable by gating, allowing to tailor the valley splitting in the range of 0 to 12 meV in WSe${}_2$/CrI${}_3$, which is equivalent to external magnetic fields of up to about 60 Tesla. Our results highlight the important impact of the twist angle and gating when employing magnetic vdW heterostructures in experimental geometries.

arXiv comment16 pages, 7 figures, 2 tables + Supplemental Material

References in corpus (79)

• Quantum ESPRESSO: a modular and open-source software project for quantum simulations of materials
• Van der Waals heterostructures
• Magic-angle graphene superlattices: a new platform for unconventional superconductivity
• Advanced capabilities for materials modelling with Quantum ESPRESSO
• 2D materials and van der Waals heterostructures
• Layer-dependent Ferromagnetism in a van der Waals Crystal down to the Monolayer Limit
• Coupled spin and valley physics in monolayers of MoS2 and other group-VI dichalcogenides
• Correlated Insulator Behaviour at Half-Filling in Magic Angle Graphene Superlattices
• Control of valley polarization in monolayer MoS2 by optical helicity
• Valley polarization in MoS2 monolayers by optical pumping
• Quantum Spin Hall Effect and Topological Field Effect Transistor in Two-Dimensional Transition Metal Dichalcogenides
• Emergent ferromagnetism near three-quarters filling in twisted bilayer graphene
• Superconductors, Orbital Magnets, and Correlated States in Magic Angle Bilayer Graphene
• Intrinsic quantized anomalous Hall effect in a moiré heterostructure
• k.p theory for two-dimensional transition metal dichalcogenide semiconductors
• Theory of Neutral and Charged Excitons in Monolayer Transition Metal Dichalcogenides
• Magnetic Control of Valley Pseudospin in Monolayer WSe2
• Tunable Phase Boundaries and Ultra-Strong Coupling Superconductivity in Mirror Symmetric Magic-Angle Trilayer Graphene
• Valley Zeeman Effect in Elementary Optical Excitations of a Monolayer WSe2
• Breaking of valley degeneracy by magnetic field in monolayer MoSe2
• Tunable Correlated Chern Insulator and Ferromagnetism in Trilayer Graphene/Boron Nitride Moiré Superlattice
• Electronic structures and theoretical modelling of two-dimensional group-VIB transition metal dichalcogenides
• Imaging Electronic Correlations in Twisted Bilayer Graphene near the Magic Angle
• Signatures of Gate-Tunable Superconductivity in Trilayer Graphene/Boron Nitride Moiré Superlattice
• Van der Waals heterostructures for spintronics and opto-spintronics
• Evidence of Gate-Tunable Mott Insulator in Trilayer Graphene-Boron Nitride Moiré Superlattice
• Untying the insulating and superconducting orders in magic-angle graphene
• Valley Splitting and Polarization by the Zeeman Effect in Monolayer MoSe2
• Colloquium: Spintronics in graphene and other two-dimensional materials
• Enhanced valley splitting in monolayer WSe2 due to magnetic exchange field
• Superconductivity in rhombohedral trilayer graphene
• Structural Semiconductor-to-Semimetal Phase Transition in Two-Dimensional Materials Induced by Electrostatic Gating
• Valley Manipulation by Optically Tuning the Magnetic Proximity Effect in WSe${}_2$/CrI${}_3$ Heterostructures
• Giant and tunable valley degeneracy splitting in MoTe2
• Graphene on transition-metal dichalcogenides: a platform for proximity spin-orbit physics and optospintronics
• Superconductivity without insulating states in twisted bilayer graphene stabilized by monolayer WSe${}_2$
• Exciton Diamagnetic Shifts and Valley Zeeman Effects in Monolayer WS${}_2$ and MoS${}_2$ to 65 Tesla
• A mechanism for anomalous Hall ferromagnetism in twisted bilayer graphene
• Half and quarter metals in rhombohedral trilayer graphene
• Revealing exciton masses and dielectric properties of monolayer semiconductors with high magnetic fields
• Trivial and inverted Dirac bands, and emergence of quantum spin Hall states in graphene on transition-metal dichalcogenides
• Magneto-Optics of Exciton Rydberg States in a Monolayer Semiconductor
• Giant Valley Splitting in Monolayer WS2 by Magnetic Proximity Effect
• Layer-Resolved Magnetic Proximity Effect in van der Waals Heterostructures
• Charge-to-Spin Conversion by the Rashba-Edelstein Effect in 2D van der Waals Heterostructures up to Room Temperature
• Strain-tunable magnetic and electronic properties of monolayer CrI3
• Strain-Based Room-Temperature Non-Volatile MoTe${}_2$ Ferroelectric Phase Change Transistor
• Spin direction controlled electronic band structure in two dimensional ferromagnetic CrI3
• Ferromagnetism in narrow bands of moiré superlattices
• Large valley splitting in monolayer WS${}_2$ by proximity coupling to an insulating antiferromagnetic substrate
• Proximity exchange effects in MoSe${}_2$ and WSe${}_2$ heterostructures with CrI${}_3$: twist angle, layer, and gate dependence
• Variation of the fundamental band gap nature in curved two-dimensional WS2
• Strain-tunable orbital, spin-orbit, and optical properties of monolayer transition-metal dichalcogenides
• Magnetic Proximity Effects in Transition-Metal Dichalcogenides: Converting Excitons
• Twisted Trilayer Graphene: a Precisely Tunable Platform for Correlated Electrons
• Twist-angle dependence of the proximity spin-orbit coupling in graphene on transition-metal dichalcogenides
• Optimal charge-to-spin conversion in graphene on transition metal dichalcogenides
• Exciton g-factors of van der Waals heterostructures from first principles calculations
• Optical investigation of monolayer and bulk tungsten diselenide (WSe${}_2$) in high magnetic fields
• Induced spin-orbit coupling in twisted graphene-TMDC heterobilayers: twistronics meets spintronics
• Observation of Magnetic Proximity Effect Using Resonant Optical Spectroscopy of an Electrically Tunable MoSe${}_2$/CrBr${}_3$ Heterostructure
• Electrically Tunable Flat Bands and Magnetism in Twisted Bilayer Graphene
• Twist-angle dependent proximity induced spin-orbit coupling in graphene/transition-metal dichalcogenide heterostructures
• Gate-tunable Spin-Galvanic Effect in Graphene Topological insulator van der Waals Heterostructures at Room Temperature
• Acoustic-phonon-mediated superconductivity in rhombohedral trilayer graphene
• In-plane critical magnetic fields in magic-angle twisted trilayer graphene
• Gate tunability of highly efficient spin-to-charge conversion by spin Hall effect in graphene proximitized with WSe${}_2$
• Asymmetric magnetic proximity interactions in MoSe${}_2$/CrBr${}_3$ van der Waals heterostructures
• Opportunities in Electrically Tunable 2D Materials Beyond Graphene: Recent Progress and Future Outlook
• Charge-to-spin conversion in twisted graphene/WSe${}_2$ heterostructures
• Band Structure and Superconductivity in Twisted Trilayer Graphene
• van der Waals Bonded Co/h-BN Contacts to Ultrathin Black Phosphorus Devices
• Scanning gradiometry with a single spin quantum magnetometer
• Giant proximity exchange and valley splitting in transition metal dichalcogenide/$h\mathrm{BN}$/(Co, Ni) heterostructures
• Twist Angle Controlled Collinear Edelstein Effect in van der Waals Heterostructures
• Engineering Proximity Exchange by Twisting: Reversal of Ferromagnetic and Emergence of Antiferromagnetic Dirac Bands in Graphene/Cr${}_2$Ge${}_2$Te${}_6$
• Manipulation of Spin Transport in Graphene/Transition Metal Dichalcogenide Heterobilayers upon Twisting
• Excitonic Magneto-Optical Kerr Effect in 2D Transition Metal Dichalcogenides Induced by Spin Proximity
• Magneto-optical Kerr effect in spin split two-dimensional massive Dirac materials

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