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Spin-orbital effects in metal-dichalcogenide semiconducting monolayers.

Reyes-Retana JA, Cervantes-Sodi F - Sci Rep (2016)

Bottom Line: The electronic and spin properties of MX2 (M = Sc, Cr, Mn, Ni, Mo &W and X = O, S, Se &Te) were obtained with FRUP, compared with the scalar relativistic pseudopotentials (SRUP) and with the available experimental results.Among the differences between FRUP and SRUP calculations are giant splittings of the valence band, substantial band gap reductions and semiconductor to metal or non-magnetic to magnetic "transitions".MoO2, MoS2, MoSe2, MoTe2, WO2, WS2 and WSe2 are proposed as candidates for spintronics, while CrTe2, with μ ~ 1.59 μB, is a magnetic metal to be experimentally explored.

View Article: PubMed Central - PubMed

Affiliation: Universidad Iberoamericana, Departamento de Física y Matemáticas, Prolongación Paseo de la Reforma 880, Lomas de Santa Fe, Mexico City, 01219, México.

ABSTRACT
Metal-dioxide &metal-dichalcogenide monolayers are studied by means of Density Functional Theory. For an accurate reproduction of the electronic structure of transition metal systems, the spin orbit interaction is considered by using fully relativistic pseudopotentials (FRUP). The electronic and spin properties of MX2 (M = Sc, Cr, Mn, Ni, Mo &W and X = O, S, Se &Te) were obtained with FRUP, compared with the scalar relativistic pseudopotentials (SRUP) and with the available experimental results. Among the differences between FRUP and SRUP calculations are giant splittings of the valence band, substantial band gap reductions and semiconductor to metal or non-magnetic to magnetic "transitions". MoO2, MoS2, MoSe2, MoTe2, WO2, WS2 and WSe2 are proposed as candidates for spintronics, while CrTe2, with μ ~ 1.59 μB, is a magnetic metal to be experimentally explored.

No MeSH data available.


DOS and orbital-projected DOS for CrTe2, MoTe2 and WTe2. (dash brown),  (solid yellow) and dxy (dash pink) are the main SRUP orbitals contributors from the VBM to the DOS (solid black). The major effect of the spin orbit reflects in the dispersion of these orbitals (solid blue). p and d orbitals are shifted for clarity. The arrows indicate the splitting of the VBM for the FRUP calculation for MoTe2.
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f4: DOS and orbital-projected DOS for CrTe2, MoTe2 and WTe2. (dash brown), (solid yellow) and dxy (dash pink) are the main SRUP orbitals contributors from the VBM to the DOS (solid black). The major effect of the spin orbit reflects in the dispersion of these orbitals (solid blue). p and d orbitals are shifted for clarity. The arrows indicate the splitting of the VBM for the FRUP calculation for MoTe2.

Mentions: Bulk CrS, CrSe and CrTe compounds, in contrast with their corresponding 2D nonmagnetic semiconductor structures, present magnetism74. The calculations for 2D CrX2 systems with FRUP yield a small effect due to the spin orbit interaction. For CrS2 and CrSe2, they remain as semiconductors (Figs 2 and 3). Differently, for CrTe2 the inclusion of spin orbit interaction turns it from a nonmagnetic semiconductor with a band gap of 0.534 eV, to a magnetic metal with a μ of 1.59 μB; in agreement with its metallic magnetic behavior reported by Lebegue et al.12. Looking at the local DOS (LDOS) in Fig. 4, it is clear that the principal contributions around the VBM and CBM, without spin-orbit effect, are mainly due to the contribution of the Cr 3d and Te 5p orbitals; specifically the , and 3dxy orbitals that disperse in some degree when the fully relativistic approximation is considered60 (Figs 2 and 4). CrTe2 presents a ΔEg = 534 meV, the largest among all the systems reported in this work. CrS2 and CrSe2 present small VBM splittings, at the K points, of 69 and 95 meV respectively. In contrast CrTe2 presents a giant splitting of 2.32 eV, with the already mentioned magnetic moment of 1.59 μB.


Spin-orbital effects in metal-dichalcogenide semiconducting monolayers.

Reyes-Retana JA, Cervantes-Sodi F - Sci Rep (2016)

DOS and orbital-projected DOS for CrTe2, MoTe2 and WTe2. (dash brown),  (solid yellow) and dxy (dash pink) are the main SRUP orbitals contributors from the VBM to the DOS (solid black). The major effect of the spin orbit reflects in the dispersion of these orbitals (solid blue). p and d orbitals are shifted for clarity. The arrows indicate the splitting of the VBM for the FRUP calculation for MoTe2.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4837337&req=5

f4: DOS and orbital-projected DOS for CrTe2, MoTe2 and WTe2. (dash brown), (solid yellow) and dxy (dash pink) are the main SRUP orbitals contributors from the VBM to the DOS (solid black). The major effect of the spin orbit reflects in the dispersion of these orbitals (solid blue). p and d orbitals are shifted for clarity. The arrows indicate the splitting of the VBM for the FRUP calculation for MoTe2.
Mentions: Bulk CrS, CrSe and CrTe compounds, in contrast with their corresponding 2D nonmagnetic semiconductor structures, present magnetism74. The calculations for 2D CrX2 systems with FRUP yield a small effect due to the spin orbit interaction. For CrS2 and CrSe2, they remain as semiconductors (Figs 2 and 3). Differently, for CrTe2 the inclusion of spin orbit interaction turns it from a nonmagnetic semiconductor with a band gap of 0.534 eV, to a magnetic metal with a μ of 1.59 μB; in agreement with its metallic magnetic behavior reported by Lebegue et al.12. Looking at the local DOS (LDOS) in Fig. 4, it is clear that the principal contributions around the VBM and CBM, without spin-orbit effect, are mainly due to the contribution of the Cr 3d and Te 5p orbitals; specifically the , and 3dxy orbitals that disperse in some degree when the fully relativistic approximation is considered60 (Figs 2 and 4). CrTe2 presents a ΔEg = 534 meV, the largest among all the systems reported in this work. CrS2 and CrSe2 present small VBM splittings, at the K points, of 69 and 95 meV respectively. In contrast CrTe2 presents a giant splitting of 2.32 eV, with the already mentioned magnetic moment of 1.59 μB.

Bottom Line: The electronic and spin properties of MX2 (M = Sc, Cr, Mn, Ni, Mo &W and X = O, S, Se &Te) were obtained with FRUP, compared with the scalar relativistic pseudopotentials (SRUP) and with the available experimental results.Among the differences between FRUP and SRUP calculations are giant splittings of the valence band, substantial band gap reductions and semiconductor to metal or non-magnetic to magnetic "transitions".MoO2, MoS2, MoSe2, MoTe2, WO2, WS2 and WSe2 are proposed as candidates for spintronics, while CrTe2, with μ ~ 1.59 μB, is a magnetic metal to be experimentally explored.

View Article: PubMed Central - PubMed

Affiliation: Universidad Iberoamericana, Departamento de Física y Matemáticas, Prolongación Paseo de la Reforma 880, Lomas de Santa Fe, Mexico City, 01219, México.

ABSTRACT
Metal-dioxide &metal-dichalcogenide monolayers are studied by means of Density Functional Theory. For an accurate reproduction of the electronic structure of transition metal systems, the spin orbit interaction is considered by using fully relativistic pseudopotentials (FRUP). The electronic and spin properties of MX2 (M = Sc, Cr, Mn, Ni, Mo &W and X = O, S, Se &Te) were obtained with FRUP, compared with the scalar relativistic pseudopotentials (SRUP) and with the available experimental results. Among the differences between FRUP and SRUP calculations are giant splittings of the valence band, substantial band gap reductions and semiconductor to metal or non-magnetic to magnetic "transitions". MoO2, MoS2, MoSe2, MoTe2, WO2, WS2 and WSe2 are proposed as candidates for spintronics, while CrTe2, with μ ~ 1.59 μB, is a magnetic metal to be experimentally explored.

No MeSH data available.