Spin–valley Hall phenomena driven by Van Hove singularities in blistered graphene

Farooq, M. Umar; Hashmi, Arqum; Ono, Tomoya; Huang, Li

doi:10.1038/s41524-020-00470-9

Cited by 5 publications

(2 citation statements)

References 56 publications

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“…Since the discovery of graphene by mechanical exfoliation [1,2], significant efforts have been made to study the applications and intrinsic properties of this monolayer. Graphene has high electrical conductivity and carrier mobility [3][4][5][6], a frictionless surface [7], and quantum Hall effects at room temperature [8][9][10]. Despite having all these nontrivial properties, graphene has a zero band gap.…”

Section: Introductionmentioning

confidence: 99%

Strain engineering in optoelectronic properties of MoSi₂N₄ monolayer: ultrahigh tunability

Alavi-Rad¹

2022

Semicond. Sci. Technol.

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Controllable optical properties are important for optoelectronic applications. Recently, the two-dimensional MoSi2N4 monolayer was successfully synthesized by chemical vapor deposition, showing remarkable stability in the ambient condition. Motivated by this achievement, herein, we investigate the electronic and optical properties of MoSi2N4 monolayer under mechanical strain through the first-principle calculations. The considered monolayer is structurally and dynamically stable. It is a semiconductor with an indirect band gap of 1.92 eV so that the size of the band gap is easily tuned under biaxial strain. By increasing the tensile strain up to 6%, the effective mass of holes increases to 3.84 me whereas the effective mass of electrons reduces to 0.43 me. In other words, under the strain of 6%, one can have strongly localized holes together with free electrons simultaneously in MoSi2N4 monolayer, which could bring fascinating features like ferromagnetism and superconductivity. Under the strain from 10% to 18%, a Mexican hat dispersion is observed in the highest valence band in such a manner that its coefficient increases from 0.28 to 2.89 eVÅ, indicating the potential thermoelectric application of MoSi2N4 monolayer under strain. Under the strain of 8%, the light absorption coefficient is improved by almost 70%. More importantly, this monolayer tolerates biaxial strain up to 18% and stays mechanically and dynamically stable, making it very promising for flexible nanoelectronics. The controllable electronic and optical properties of MoSi2N4 monolayer may open up an important path for exploring next-generation optoelectronic applications.

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Section: Introductionmentioning

confidence: 99%

Strain engineering in optoelectronic properties of MoSi₂N₄ monolayer: ultrahigh tunability

Alavi-Rad¹

2022

Semicond. Sci. Technol.

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“…The local chirality (whether the vortex whirls clockwise or counter-clockwise) is alternating for neighboring K points, i.e., the spin texture is antichiral. Note that the term antichiral has been recently introduced in the field of skyrmions [84] while a few works have reported the antichiral spin textures in k-space without employ- ing this terminology [47,85,86]. On the other hand, the p321 system exhibits radial spin textures of alternating 'sink' and 'source' around K points.…”

Section: Spin Textures In K-spacementioning

confidence: 99%

Activating magneto-electric-optical properties by twisting antiferromagnetic bilayers

Yananose¹,

Radaelli²,

Cuoco³

et al. 2022

Preprint

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Twisting in bilayers introduces structural chirality with two enantiomers, i.e., left-and right-hand bilayers, depending on the oriented twist angle. The interplay between this global chirality and additional degrees of freedom, such as magnetic ordering and the local octahedral chirality arising from the geometry of the bonds, can yield striking phenomena. In this work, we focus on collinear antiferromagnetic CrI3 twisted homo-bilayers, which are characterized by a staggered octahedral chirality in each monolayer. Using symmetry analysis, density functional theory and tight-binding model calculations we show that layers twisting can lower the structural and magnetic point-group symmetries, thus activating pyroelectricity and the magneto-optical Kerr effect, which would otherwise be absent in untwisted antiferromagnetic homo-bilayers. Interestingly, both electric polarization and Kerr angle are controllable by the twist angle and their sign is reversed when switching from left-to right-twisted bilayers. We further unveil the occurrence of unconventional vortices with spin textures that alternate opposite chiralities in momentum space. These findings demonstrate that the interplay between twisting and octahedral chirality in magnetic bilayers and related van der Waals heterostructures represents an extraordinary resource for tailoring their physical properties for spintronic and optoelectronic applications.

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Sign-reversible valley-dependent Berry phase effects in 2D valley-half-semiconductors

Zhou

Zhang

et al. 2021

npj Comput Mater

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Manipulating valley-dependent Berry phase effects provides remarkable opportunities for both fundamental research and practical applications. Here, by referring to effective model analysis, we propose a general scheme for realizing topological magneto-valley phase transitions. More importantly, by using valley-half-semiconducting VSi2N4 as an outstanding example, we investigate sign change of valley-dependent Berry phase effects which drive the change-in-sign valley anomalous transport characteristics via external means such as biaxial strain, electric field, and correlation effects. As a result, this gives rise to quantized versions of valley anomalous transport phenomena. Our findings not only uncover a general framework to control valley degree of freedom, but also motivate further research in the direction of multifunctional quantum devices in valleytronics and spintronics.

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Spin–valley Hall phenomena driven by Van Hove singularities in blistered graphene

Cited by 5 publications

References 56 publications

Strain engineering in optoelectronic properties of MoSi₂N₄ monolayer: ultrahigh tunability

Strain engineering in optoelectronic properties of MoSi₂N₄ monolayer: ultrahigh tunability

Activating magneto-electric-optical properties by twisting antiferromagnetic bilayers

Sign-reversible valley-dependent Berry phase effects in 2D valley-half-semiconductors

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Spin–valley Hall phenomena driven by Van Hove singularities in blistered graphene

Cited by 5 publications

References 56 publications

Strain engineering in optoelectronic properties of MoSi2N4 monolayer: ultrahigh tunability

Strain engineering in optoelectronic properties of MoSi2N4 monolayer: ultrahigh tunability

Activating magneto-electric-optical properties by twisting antiferromagnetic bilayers

Sign-reversible valley-dependent Berry phase effects in 2D valley-half-semiconductors

Contact Info

Product

Resources

About

Strain engineering in optoelectronic properties of MoSi₂N₄ monolayer: ultrahigh tunability

Strain engineering in optoelectronic properties of MoSi₂N₄ monolayer: ultrahigh tunability