Magnetic properties of monolayer WSe2 doped with nonmagnetic metal and nonmetal atoms

Abstract

Electronic and magnetic properties of WSe2 monolayer with different nonmagnetic metal and nonmetal dopants have been studied by the DFT method. Nonmagnetic metal (Ag, Al, Li, Mg, and Na) and nonmetal (B, C, F, N, and O) dopants prefer to W and Se substitutions, respectively. Magnetism has been induced by Al doping. Then, we further have considered the effect of strain on the magnetism in Al-doped WSe2 monolayer. We have applied an isotropic strain on the system. On one hand, the magnetism disappears while the compressive strain is applied. On the other hand, the magnetism keeps stable under the tensile strain. Moreover, we also investigate the magnetic coupling in two-Al-doped WSe2 structures under the tensile strain. Interestingly, a tunable magnetic coupling has been observed. As the tensile strain increases, the magnetic coupling of two Al atoms switches from nonmagnetic (NM) to ferromagnetic (FM) due to the p-p hybridization between Al and Se atoms. These fascinating controllable magnetic properties are desired for spintronic applications.

Defect-Mediated Charge-Carrier Trapping and Nonradiative Recombination in WSe2 Monolayers

“…Electronic structure calculations and geometry optimizations were done within spin-restricted density-functional theory (DFT) using the Quantum Espresso software package . We employed spin-restricted DFT because pristine TMD materials are nonmagnetic , and because the ground states of all of the defective WSe 2 monolayers considered here were as well (Table S1). The Kohn–Sham one-electron wave functions for the valence electrons of W (5s 2 5p 6 5d 4 6s 2 ) and Se (4s 2 4p 4 ) were expanded in a plane-wave basis set and electron–ion (screened nuclei) interactions were represented by optimized norm-conserving pseudopotentials. − We used the generalized gradient approximation (GGA) of Perdew, Burke, and Ernzerhof (PBE) for the DFT exchange-correlation (XC) functional.…”

Quantum magnetic phenomena in engineered heterointerface of low-dimensional van der Waals and non-van der Waals materials

“…Emergence of magnetic behavior in non-magnetic systems as a result of strain was also predicted by theoretical calculation. [119][120][121] Induced magnetism was predicted in the WSe 2 /SnS 2 heterostructure by hole doping when the interlayer strain exceeded 15%, which is a result of the competition among the d-sub orbitals of W in the distorted crystal field. 120 However, there is no experimental realization of induced magnetism in nonmagnetic systems via substrateinduced strain mechanisms.…”

Defect‐Engineered Magnetic Field Dependent Optoelectronics of Vanadium Doped Tungsten Diselenide Monolayers

“…Monolayer semiconducting transition metal dichalcogenides (TMDCs) of group IV transition metals, such as MoS 2 , WS 2 , and WSe 2 , exhibit direct band gaps in the visible range and a weak dielectric screening, with the latter significantly Calculations for TMDC monolayers, such as MoS 2 and WS 2 , suggest that doping with manganese, nickel, niobium, tantalum or vanadium can induce ferromagnetic order with Curie temperatures up to 170 K. [8,15,16] Among different host materials, monolayer WSe 2 is deemed especially suitable due to its good ambipolar gate tunability and larger spin-orbit splitting compared to the Mo-based TMDCs, which can be beneficial for stabilizing the magnetic order. [13,[17][18][19][20][21] Furthermore, (doped) WSe 2 bulk crystals can be grown at low defect densities, enabling proof-of-concept devices, but also high quality wafer-scale monolayers can be grown by metal organic chemical vapor deposition (CVD), ensuring scalability and applicability. [2,13,22] In vanadium-doped WSe 2 , theoretical and experimental works have provided first evidence for a room temperature, long-range, (ferro)magnetic order.…”

“…[ 11–14 ] Calculations for TMDC monolayers, such as MoS 2 and WS 2 , suggest that doping with manganese, nickel, niobium, tantalum or vanadium can induce ferromagnetic order with Curie temperatures up to 170 K. [ 8,15,16 ] Among different host materials, monolayer WSe 2 is deemed especially suitable due to its good ambipolar gate tunability and larger spin‐orbit splitting compared to the Mo‐based TMDCs, which can be beneficial for stabilizing the magnetic order. [ 13,17–21 ] Furthermore, (doped) WSe 2 bulk crystals can be grown at low defect densities, enabling proof‐of‐concept devices, but also high quality wafer‐scale monolayers can be grown by metal organic chemical vapor deposition (CVD), ensuring scalability and applicability. [ 2,13,22 ]…”