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Adjusting the electronic and magnetic properties of materials by strain engineering is an effective strategy to improve the performance of electronic and spin electronic devices. In this paper, we study the electronic and magnetic properties of Cr 2 C and Cr 2 CX 2 (X = F, O,OH) under mechanical strain based on density functional theory. In the strain-free state, Cr 2 C and Cr 2 CO 2 are in the ferromagnetic (FM) metallic ground states, while Cr 2 CF 2 and Cr 2 C(OH) 2 are in the antiferromagnetic (AFM) semiconducting states. Applying tensile strain can enhance the magnetic moments of the Cr atoms of all the Cr 2 C and Cr 2 CX 2 (X = F, O, OH) systems. The electronic structure can also be affected with the increase of strain, e.g., resulting in narrowing of the band gap of the AFM semiconducting systems (Cr 2 CF 2 and Cr 2 C(OH) 2) and enhancing the spin-splitting of the FM metallic systems (Cr 2 C and Cr 2 CO 2). The results indicate a possible broadened applicability of strained Cr 2 C-based MXenes in future spintronics. • In the strain-free state, Cr 2 C and Cr 2 CO 2 are in the ferromagnetic (FM) metallic ground states, while Cr 2 CF 2 and Cr 2 C(OH) 2 are in the antiferromagnetic (AFM) semiconducting states. • Applying tensile strain can enhance the magnetic moments of the Cr atoms of all the Cr 2 C and Cr 2 CX 2 (X = F, O, OH) systems. • Applying tensile strain can change the electronic properties and magnetic properties of the system. [ABSTRACT FROM AUTHOR]

Monolayer MoTe 2 exhibits excellent electronic properties which can be widely utilized in opto- and nanoelectronic fields. Intrinsic defects are commonly formed in MoTe 2 growth, which would significantly influence the nature of the material. We systematically studied the electronic and magnetic properties of intrinsic defects including point defects and boundaries in monolayer MoTe 2 by means of first-principles calculations based on density functional theory (DFT). Results show that the defective structures could effectually induce magnetic moment with the exception of V Te , V Te2 , V MoTe3 , V MoTe6 as well as the 4|4a boundary. Briefly speaking, boundary defects are easier to induce magnetic generation than point defects. Additionally, the electronic structures of the defective structures were systematically analyzed to understand the origin of the observed magnetism. Moreover, different application foreground could be anticipated through the modulation of defect structures, for instance, 4|4b and 8|8b boundaries can form a metallic interface as well as the 6|6a structure can form spin gapless semiconductor(SGS), respectively. Our calculated results suggest that intrinsic structural defects in monolayer MoTe 2 could open a new platform to extend the application in spintronics and electronics. [ABSTRACT FROM AUTHOR]

Achieving high light absorption efficiency and low photogenerated carrier recombination rates is critical in the production of H 2 by photoelectrochemical water splitting. Antimony selenide (Sb 2 Se 3) has recently received much attention due to its favorable optoelectronic properties, low cost and unique nanorod structure. Herein, we constructed coral-like Sb 2 Se 3 /SnS 2 heterojunction by introducing SnS 2 with a nanosheet structure, which contributes to enhanced light absorption and provides more reaction sites. On this basis, synergistic optimization is carried out by the bilayer Sb 2 Se 3 structure and ferrihydrite (Fh) to effectively inhibit charge recombination at the interface and facilitate electron transport. Compared to monolayer Sb 2 Se 3 (1.54%), the IPCE value of bilayer Sb 2 Se 3 /SnS 2 /Fh can reach 20.56% (735 nm). The prepared bilayer Sb 2 Se 3 /SnS 2 /Fh has a maximum photocurrent density of approximately − 1.0 mA cm−2 at 0 V RHE , continuous testing for 1 h compared to monolayer Sb 2 Se 3 still maintains more than 4 times improvement. This work provides a basis for the development of high efficiency and low cost Sb 2 Se 3 -based optoelectronic devices. [Display omitted] • The bilayer Sb 2 Se 3 structure was constructed by sequential deposition. • A combination between 1D Sb 2 Se 3 nanorods and 2D SnS 2 nanosheets has been achieved. • Surface modification using ferrihydrite as an interface engineering material. • Optimized photoelectrode current density is 50 times higher than original sample. • The PEC mechanism of bilayer Sb 2 Se 3 /SnS 2 /Fh photoelectrode was proposed. [ABSTRACT FROM AUTHOR]