Chirality-induced spin texture switching in twisted bilayer graphene

Yananose, Kunihiro; Cantele, Giovanni; Lucignano, P.; Cheong, Sang‐Wook; Yu, Jaejun; Stroppa, Alessandro

doi:10.1103/physrevb.104.075407

Cited by 13 publications

(7 citation statements)

References 77 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Despite the magnetic effects on moiré superlattices not being extensively explored, our results agree with previous studies indicating that changes in the neighborhoods and relaxation mechanisms play a key role in modifying the electronic and structural properties of graphene [ 30–34 ] and metal dichalcogenide systems. [ 35–38 ]…”

Section: Resultssupporting

confidence: 91%

Tuning Magnetic Order in CrI3 Bilayers via Moiré Patterns

León

Velásquez

Caro-Lopera

et al. 2022

Advcd Theory and Sims

View full text Add to dashboard Cite

Commensurable twisted bilayers can drastically change the magnetic properties of chromium trihalide layered compounds, which opens novel opportunities for tuning magnetic states through layer rotations. Here, a mathematical approach to obtain moiré patterns in twisted hexagonal bilayers by performing a certain commensurable rotation 𝜽 over one layer is presented. To test the approach, moiré structures with 𝜽 = 21.79 • and 32.20 • in the phases R 3 and C2/m of CrI 3 are obtained via the related methodology. For comparison purposes, a non-shifted CrI 3 structure is also considered. Electronic and magnetic properties of the so-obtained systems are computed by ab initio methodologies. Results show the presence of rotation-angle-dependent magnetic configurations and steep modifications of the dispersion bands due to variations in the nearest and next nearest distances among layers of Cr atoms. Modifications obtained from these commensurable rotations are discussed on the basis of competition among different energy contributions due to changes in the atomic neighborhood.

show abstract

Section: Resultssupporting

confidence: 91%

Tuning Magnetic Order in CrI3 Bilayers via Moiré Patterns

León

Velásquez

Caro-Lopera

et al. 2022

Advcd Theory and Sims

View full text Add to dashboard Cite

show abstract

“…CrI 3 monolayers and untwisted bilayers are not globally chiral, because both OC enantiomers R and L are equally represented, thus forming a 'racemic structure.' This situation changes radically in the TBLs: in fact, the twist of the two layers naturally introduces global chirality [60], which can interact with OC (a chiral sublattice degree of freedom) to reduce symmetry further in a variety of ways. We have shown that commensurate CrI 3 TBLs have different layer-group symmetries depending on both OC stacking and the twist angle.…”

Section: Discussionmentioning

confidence: 99%

“…In fact, this result can be explained as a consequence of the interplay between OC and twist chirality. One can note that the twist itself induces global chirality [59,60] (right-and left-twists forming an enantiomeric pair) -in other words, improper rotations, such as mirror, inversion, and roto-inversion, must be absent in the twisted system. Consequently, the only symmetry operators that could connect the two monolayers are 2-fold rotations with horizontal axes.…”

Section: Structures and Symmetriesmentioning

confidence: 99%

Activating magneto-electric-optical properties by twisting antiferromagnetic bilayers

Yananose¹,

Radaelli²,

Cuoco³

et al. 2022

Preprint

Self Cite

View full text Add to dashboard Cite

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.

show abstract

“…The chirality of TBG seems to induce spin textures around the K point of the Brillouin zone with alternating vortex-like textures [334]. The helicity of each vortex is inverted by changing the chirality.…”

Section: Magic Angle Twisted Bilayer Graphenementioning

confidence: 97%

Mechanical, electronic, optical, piezoelectric and ferroic properties of strained graphene and other strained monolayers and multilayers: an update

Naumis,

Herrera,

Poudel

et al. 2023

Rep. Prog. Phys.

View full text Add to dashboard Cite

This is an update of a previous review on the subject \cite{Naumis_2017}. Experimental and theoretical advances for straining graphene and other metallic, insulating, ferroelectric, ferroelastic, ferromagnetic and multiferroic 2D materials have been considered. Specific topics of discussion include: (i) methods to induce valley and sublattice polarisation ($\mathbf{P}$) in graphene, (ii) time-dependent strain and its impact on graphene's electronic properties, (iii) the role of local and global strain on superconductivity and other highly correlated and/or topological phases of graphene, inducing polarisation $\mathbf{P}$ on hexagonal boron nitride monolayers {\it via} strain, (iv) measuring strain, and modifying through strain the optoelectronic properties of transition metal dichalcogenides, (v) ferroic 2D materials with intrinsic elastic ($\sigma$), electric ($\mathbf{P}$) and magnetic ($\mathbf{M}$) polarisation under strain, as well as incipient 2D multiferroics and (vi) moir'e bilayers exhibiting flat electronic bands and exotic quantum phase diagrams, and other bilayer or few-layer systems exhibiting ferroic orders tunable by rotations and shear strain. The review features the extremely recent experimental realizations of a tunable two-dimensional Quantum Spin Hall effect in germanene, of monoelemental 2D ferroelectric bismuth, and 2D multiferroic NiI$_2$. The document was structured for a discussion of effects taking place in monolayers first, followed by discussions concerning bilayers and few-layers, and it represents a fresh and up-to-date overview of exciting and newest developments on the fast-paced field of 2D materials.

show abstract

Chirality-induced spin texture switching in twisted bilayer graphene

Cited by 13 publications

References 77 publications

Tuning Magnetic Order in CrI3 Bilayers via Moiré Patterns

Tuning Magnetic Order in CrI3 Bilayers via Moiré Patterns

Activating magneto-electric-optical properties by twisting antiferromagnetic bilayers

Mechanical, electronic, optical, piezoelectric and ferroic properties of strained graphene and other strained monolayers and multilayers: an update

Contact Info

Product

Resources

About