Robust intrinsic ferromagnetism and half semiconductivity in stable two-dimensional single-layer chromium trihalides
By Wei‐Bing Zhang, Qian Qu, Peng Zhu, C. Lam. 2015
474 citations recorded by the source corpus.
Two-dimensional (2D) intrinsic ferromagnetic (FM) semiconductors are crucial to develop low-dimensional spintronic devices. Using density functional theory, we show that single-layer chromium trihalides (SLCTs) (CrX3, X = F, Cl, Br and I) constitute a series of stable 2D intrinsic FM semiconductors. A free-standing SLCT can be easily exfoliated from the bulk crystal, due to a low cleavage energy and a high in-plane stiffness. Electronic structure calculations using the HSE06 functional indicate that both bulk and single-layer CrX3 are half semiconductors with indirect gaps and their valence and conduction bands are fully spin-polarized in the same spin direction. The energy gaps and absorption edges of CrBr3 and CrI3 are found to be in the visible frequency range, which implies possible opto-electronic applications. Furthermore, SLCTs are found to possess a large magnetic moment of 3 μB per formula unit and a sizable magnetic anisotropy energy. The magnetic exchange constants of SLCTs are then extracted using the Heisenberg spin Hamiltonian and the microscopic origins of the various exchange interactions are analyzed. A competition between a near 90° FM superexchange and a direct antiferromagnetic (AFM) exchange results in a FM nearest-neighbour exchange interaction. The next and third nearest-neighbour exchange interactions are found to be FM and AFM, respectively, and this can be understood by the angle-dependent extended Cr–X–X–Cr superexchange interaction. Moreover, the Curie temperatures of SLCTs are also predicted using Monte Carlo simulations and the values can be further increased by applying a biaxial tensile strain. The unique combination of robust intrinsic ferromagnetism, half semiconductivity and large magnetic anisotropy energies renders the SLCTs as promising candidates for next-generation semiconductor spintronic applications.
Subfields: Electronic, Optical and Magnetic Materials, Materials Chemistry
View Paper: https://www.semanticscholar.org/paper/5771edb87f8dfb3dbcad8a8e968ad71afcdfc279
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In Electronic, Optical and Magnetic Materials
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Citations in the corpus
- Crystal and Magnetic Structures in Layered, Transition Metal Dihalides and Trihalides (2017, background): “3 J/m2, which is smaller than that of graphite [16,17,93].”
- On the origin of magnetic anisotropy in two dimensional CrI3 (2017, result): “Both experimental results [2, 19] and DFT calculations [20, 21] show that CrI3 is an semiconducting material with a the band-gap of 1.”
- Magnetism, symmetry and spin transport in van der Waals layered systems (2021, unknown): “This class of new layered vdW materials is particularly vast, and includes transition metal dichalcogenides 22,23 (TMDs), such as CrSe 2 , VSe 2 , CrTe 2 , transition metal trihalides 24–26 (CrI 3 , CrCl 3 ) and transition metal phosphorous trichalcogenides 27 (NiPS 3 , MnPS 3 , etc.).”
- Dirac Magnons in Honeycomb Ferromagnets (2017, unknown): “Given the large diversity of transition metal trihalides [36,45], metamaterials generated via top-down and bottomup nanotechnology, and cold atom systems that can implement bosonic Hamiltonians for honeycomb and other nonBravais lattices, our predictions are highly relevant and can be extensively ch”
- First principles design of spintronics materials (2016, background): “pointed out that through exfoliation, single layer of CrX3 can be obtained [116].”
- Probing and controlling magnetic states in 2D layered magnetic materials (2019, unknown): “Values of the super-exchange integrals for specific materials are obtained from results from electronic structure calculations (from either the Hubbard-type Hamiltonian or ab initio methods) 8–12, 14, 41, 69 .”