研究目的
Investigating the valley and spin splitting in monolayer TX2/antiferromagnetic MnO van der Waals heterostructures using first-principles calculations to explore their potential applications in spintronic and valleytronic devices.
研究成果
The integration of TX2 monolayers with antiferromagnetic MnO induces significant valley and spin splittings due to broken time-reversal symmetry and strong interlayer coupling. The splittings and doping types (p- or n-type) can be tuned by stacking patterns and substrate termination, making these heterostructures promising for applications in valleytronics and spintronics. Charge transfer and hybridization at the interface are key factors, and the findings suggest potential for device applications such as valley filters.
研究不足
The calculations are based on theoretical models and may not fully capture experimental conditions. The use of DFT with GGA-PBE may underestimate band gaps. The study assumes ideal heterostructures without defects or impurities, and the effects of temperature (e.g., Néel temperature of MnO at 118 K) are not extensively discussed. Experimental validation is not provided.
1：Experimental Design and Method Selection:
The study employs first-principles calculations based on density functional theory (DFT) using the Vienna ab-initio simulation package (VASP). The generalized gradient approximation (GGA) with Perdew-Burke-Emzerhof (PBE) parametrization is used for exchange-correlation potential, and DFT-D2 dispersion correction is applied for van der Waals interactions. Spin-orbit coupling (SOC) is included in band structure calculations. DFT+U approach is used for on-site interactions in Mn-3d orbitals with U=4.9 eV and J=0.86 eV.
2：9 eV and J=86 eV.
Sample Selection and Data Sources:
2. Sample Selection and Data Sources: The models include monolayer MoS2, WS2, MoSe2, WSe2, and antiferromagnetic MnO(111) substrate. The heterostructures are constructed with six bilayers of MnO (12 atomic layers) passivated with hydrogen to avoid surface states. Lattice constants are based on experimental and previous computational data.
3：List of Experimental Equipment and Materials:
Computational software (VASP) is used; no physical equipment is mentioned.
4：Experimental Procedures and Operational Workflow:
Structures are relaxed with convergence criteria of energy 1e-5 eV and force 0.01 eV/?. A vacuum thickness of 20 ? is used to avoid interactions. Band structures and density of states are calculated with SOC along the [001] zone axis. Charge density differences are computed to analyze binding mechanisms.
5：01 eV/?. A vacuum thickness of 20 ? is used to avoid interactions. Band structures and density of states are calculated with SOC along the [001] zone axis. Charge density differences are computed to analyze binding mechanisms.
Data Analysis Methods:
5. Data Analysis Methods: Data is analyzed using k-mesh convergence tests (9x9x1), binding energy calculations, and analysis of spin and valley splittings at K and K' points in the Brillouin zone.
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