The electronic structure of black phosphorene (BP)/monolayer 1H-XT2 (X = Mo, W; T = S, Se, Te) two dimensional (2D) van der Waals heterostructures have been calculated by the first-principles method. It is found that the electronic band structures of both BP and XT2 are preserved in the combined van der Waals heterostructures. The WSe2/BP van der Waals heterostructure demonstrates a type-I band alignment, but the MoS2/BP, MoSe2/BP, MoTe2/BP, WS2/BP and WTe2/BP van der Waals heterostructures demonstrate a type-II band alignment. In particular, the n-type XT2/p-type BP van der Waals heterostructures can be applied in p-n diode and logical devices. Strong spin splitting appears in all of the heterostructures when considering the spin orbital coupling. Our results play a significant role in the prediction of novel 2D van der Waals heterostructures that have potential applications in spin-filter devices, spin field effect transistors, optoelectronic devices, etc.

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selection rules have been predicted in the 2H-phase TMDs due to the space inversion asymmetry. [9] The Janus monolayers are a new class of 2D materials with the mirror structure asymmetry, which can be formed by replacing an atomic layer of monolayer with other atoms. Since the discovery of Janus graphene, [10] the 2D Janus materials have attracted tremendous interest. [11-15] The Janus TMDs MXY (M = Mo, W; X, Y = S, Se, Te; X ≠ Y) monolayers show intrinsic dipole and piezoelectric effects. [12] The piezoelectric coefficients of Janus NN′X 2 (N, N′ = Ga, In; N ≠ N'; X = S, Se, Te) can be increased up to over four times of the maximum value in the perfect monolayers. [13] Moreover, the Rashba-type spin splitting induced by spin-orbit coupling (SOC) and tunable carrier mobility appear in the Janus MoSSe monolayer. [14,15] Obviously, 2D Janus MXY and NN′X 2 monolayers with the structure symmetry breaking have potential applications in piezoelectric and electronic devices. The few layer Janus MoSSe and TiSO (ZrSO, HfSO) monolayers have suitable band gaps and optimal redox potentials for water splitting, which provide numerous opportunities for photocatalysts. [11,15] For Janus TMDs materials, Lu et al. have first grown the Janus MoSSe structure by selenizing the MoS 2 monolayer. [16] Zhang et al. also synthesized a Janus MoSSe monolayer by substituted sulfurization reaction for MoSe 2 monolayer. [17] The successful synthesis and novel properties of the 2D Janus materials could promote the development of nanoscale devices, such as the ultra-sensitive detectors, field-effect transistors, and sensors. [18] However, few results on the 2D Janus materials with intrinsic magnetism are reported, which limit the applications of 2D Janus monolayers in the low-dimensional spintronic devices. Among the 2D intrinsic magnetic materials that can be experimentally reported (VSe 2 , FePS 3 , MnPSe 3 , Cr 2 Ge 2 Te 6 , CrI 3 , etc.), [19-23] the CrI 3 monolayer with a Curie temperature (T C) of 45 K has been extensively studied due to its fascinating magnetic properties. [24-27] The 2D CrI 3 monolayer is ferromagnetic (FM), but the CrI 3 bilayer has the antiferromagnetic (AFM) interlayer order, where the magnetic properties can be manipulated by the gate voltage or magnetic field. [24-27] Strain is an effective approach to modulate the electronic structure and magnetic properties of the low-dimensional materials due Two-dimensional (2D) Janus monolayers with mirror asymmetry have been found to possess extraordinary physical characteristics, meaning they could find applications in optoelectronic, electronic, and electromechanical devices. However, 2D Janus materials with intrinsic magnetism are rare. The electronic structure and magnetic properties of Janus Cr 2 I 3 X 3 (X = Br, Cl) monolayers are investigated by first-principles calculations. Janus Cr 2 I 3 X 3 monolayers are an indirect band gap semiconductor with good stability, intrinsic ferromagnetism, and electric polarization. Cr 2 I 3 Br 3 monolayer is a half semiconductor with...

We explore the electronic structure of two-dimensional (2D) MnPSe3/MoS2 van der Waals (vdW) heterostructures based on density functional theory. A novel spin splitting at the valance band maximum of MnPSe3 appears in some specific stacking models due to Mn d orbital hybridization. The simultaneous spin and valley splitting can be achieved by interfacial coupling, which is attractive for manipulation of the valley and spin degrees of freedom. More importantly, due to the antiferromagnetic ordering of manganese, the opposite spin moments at K and K′ valleys can be observed by transforming configurations, which realizes the tunable spin splitting states. Our theoretical work opens up the opportunities of valley and spin related applications of MnPSe3/MoS2 vdW heterostructures and offers a practical avenue for exploring novel devices based on the spin and valley degrees of freedom.

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We perform an ab initio simulation on the structural and electronic properties of van der Waals monolayer arsenene/FeCl2 heterostructures. Spin splitting appears at the conduction band minimum of arsenene due to interfacial coupling between As p and Cl p, Fe d states in the spin-down channel. The maximum splitting energy is 123 meV in all stacking configurations. Moreover, the splitting energy can be tuned by a perpendicular electric field. At a field of 5 V/nm, the spin-splitting direction can be inversed, and the splitting energy is −66 meV. Additionally, the positive electric field makes the system turn from an Ohmic contact into a Schottky one, which realizes a continuous modulation on the barrier height. More importantly, the electric control of spin-splitting inversion can be converted into an electric potential difference in arsenene according to the anomalous Hall effect. The transformation from spin-manipulation information to electric signal is useful in spintronic devices.

The superlattice of energetically stable La 2/3 Sr 1/3 MnO 3 and tetragonal BiFeO 3 is investigated by means of density functional theory. The superlattice as a whole exhibits a half-metallic character, as is desired for spintronic devices. The interfacial electronic states and exchange coupling are analyzed in details. We demonstrate that the interfacial O atoms play a key role in controlling the coupling. The higher ferroelectricity of tetragonal BiFeO 3 and stronger response to the magnetic moments in the La 2/3 Sr 1/3 MnO 3 /BiFeO 3 superlattice show a strongly enhanced electric control of the magnetism as compared to the rhombohedral one. Therefore, it is particularly practical interest in the magnetoelectrically controlled spintronic devices.

The combination-dependent electronic structure, magnetic anisotropy and Dzyaloshinskii–Moriya interaction in Janus Cr2I3X3 (X = Br, Cl) bilayers.