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Realizing the rational control of two-dimensional valleytronics is appealing for potential applications in valleytronic devices. Using density functional theory method, we systematically study the magnetoelectronic coupling properties in ferrovalley/ferroelectricity van der Waals (vdW) heterostructure, ScI2/Ga2STe2. Interestingly, an on/off transition of the valley nature is found for this multiferroic ScI2/Ga2STe2 heterostructure. Under the Ga2STe2-P↑ polarization state, the heterostructure shows a ferromagnetic (FM) semiconducting feature with valley polarization, while it turns out to be FM metal when the ferroelectric (FE) polarization is switched to Ga2STe2-P↓; therefore, a switchable valleytronic device can be realized by altering the FE polarization direction. Furthermore, it is found that such switchable valleytronic behaviors of the ScI2/Ga2STe2 heterostructure can be modulated by applying biaxial strains for both FE polarization directions. The research of nonvolatile electrical control of valley splitting in the two-dimensional ScI2/Ga2STe2 multiferroic heterostructure provides a way for designing all-in-one valleytronic devices. [ABSTRACT FROM AUTHOR]

The integration of two-dimensional heterostructure materials remains a fundamental way for the manipulation of spintronics in practical applications. Here, we predicted the transform of stripy antiferromagnetic (AFM) CoI2 and MnBr2 monolayers to interlayer AFM CoI2/MnBr2 heterostructure with intralayer ferromagnetic orders by using density functional theory. Interestingly, the CoI2/MnBr2 heterostructure exhibits a typical bipolar magnetic semiconducting state with type-I band alignments. Moreover, the half-metal/semiconductor transition and spin-up/spin-down polarization switching in CoI2/MnBr2 heterostructure can be effectively triggered by electron/hole doping. Our study provides the potential of AFM spintronics for information storage and processing. [ABSTRACT FROM AUTHOR]

The interlayer coupling in two-dimensional van der Waals heterostructures (HSs) has become a promising platform for manipulating physical and chemical properties. Here, the interlayer coupling-dependent electronic and magnetic properties of the VI2/V3I8 heterostructure are systematically explored by first-principles calculations. Our results showed that the VI2/V3I8 heterostructure is a robust ferromagnetic (FM) half-metal (HM) with a high Curie temperature (TC) of about 467 K. Interestingly, the electromagnetic properties of the HS can be adjusted by varying the interlayer distance. When the interlayer distance is reduced, the HS undergoes a FM HM - AFM HM -AFM metal transition. While the AFM HS can be regarded as bipolar magnetic HM with reversible spin polarized currents on the VI2 and V3I8 monolayers, respectively, when the interlayer distance is less than 2.51 Å. Besides, the electronic properties can also be adjusted under external strains. Our findings provide a promising platform for 2D heteromaterials, which hold great potential for application in nanoelectronic and spintronic devices. [ABSTRACT FROM AUTHOR]

Although much efforts have been made into exploration of quantum anomalous Hall (QAH) effects in theory and experiment, the QAH materials with high Chern number are still rare to people. Here, by first-principles calculations, we theoretically predicted stable 2D robust QAH monolayers, Ti3X5 (X = S, Se) with high Chern number |C| = 2. In the absence of spin–orbital coupling (SOC), the ferromagnetism polarizes the system into a half semimetal with eight Weyl points in the whole Brillouin zone. When SOC is turned on, the bandgap is opened with two chiral edge modes. Additionally, a topological phase transition from C = −2 to C = 2 is realized by rotating the magnetization direction from z axis to −z axis. In addition, a phase transition from C = −2 to C = 0 can be manipulated by applying external strains or varying electronic correlation Ueff. Our work provides potential high Chern number QAH candidates for the practical electronic application. [ABSTRACT FROM AUTHOR]

Searching for two-dimensional materials combining both magnetic order and topological order is of great significance for quantum devices and spintronic devices. Here, a class of two-dimensional transition metal borides, TM2B3 (TM = Ti–Ni), with high stability and stable antiferromagnetic (AFM) orders was predicted by using the first-principles method. The result shows that they possess large magnetic anisotropy energy and high critical temperature. Interestingly, Mn2B3 monolayer is confirmed to be AFM Dirac node line semimetal with several Dirac points near the Fermi level. Detailed analysis of the irreducible representations shows that the nodal lines are protected by the horizontal mirror symmetry Mz. Our findings provide an excellent platform for exploring topological and magnetic materials ready for the next generation of spintronic devices. [ABSTRACT FROM AUTHOR]

The geometrical structure, electronic and magnetic properties of B-endoped C60 (B@C60) ligand sandwich clusters, TM&(B@C60)2 (TM = V, Cr), and their one-dimensional (1D) infinite molecular wires, [TM&(B@C60)]∞, have been systematically studied using first-principles calculations. The calculations showed that the TM atoms can bond strongly to the pentagonal (η5-coordinated) or hexagonal rings (η6-coordinated) of the endoped C60 ligands, with binding energies ranging from 1.90 to 3.81 eV. Compared to the configurations with contrast-bonding characters, the η6- and η5-coordinated bonding is energetically more favorable for V-(B@C60) and Cr-(B@C60) complexes, respectively. Interestingly, 1D infinite molecular wire [V&(B@C60)-η6]∞ is an antiferromagnetic half-metal, and 1D [Cr&(B@C60)-η5]∞ molecular wire is a ferromagnetic metal. The tunable electronic and magnetic properties of 1D [TM&(B@C60)]∞ SMWs are found under compressive and tensile stains. These findings provide additional possibilities for the application of C60-based sandwich compounds in electronic and spintronic devices. [ABSTRACT FROM AUTHOR]