Manipulating Topological Domain Boundaries in the Single-Layer Quantum Spin Hall Insulator 1T′–WSe<sub>2</sub>

Pedramrazi, Zahra; Herbig, Charlotte; Pulkin, Artem; Tang, Shujie; Phillips, Madeleine; Wong, Dillon; Ryu, Hyejin; Pizzochero, Michele; Chen, Yi; Wang, Feng; Mele, E. J.; Shen, Zhi‐Xun; Mo, S.-K.; Yazyev, Oleg V.; Crommie, Michael F.

doi:10.1021/acs.nanolett.9b02157

Cited by 37 publications

(35 citation statements)

References 27 publications

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“…We note that during the review process of this work, 2D ferroelasticity is also reported in layered perovskites 32 , but only limited to crystals ~10 micron thick in contrast to the 2D flakes down to few-layer thickness investigated in our work. The demonstrated 2D ferroelasticity in both works further indicates its wide presence in vdW materials with anisotropic lattice strain, such as the 1T’ TMDs with Peierls distortion 1 , 17 , 28 , 52 , 56 and 2D ferroelectrics such as the SnTe family 13 , 57 , 58 . Considering a variety of emerging functionalities possessed by these vdW materials, ranging from quantum spin Hall effect to in-plane ferroelectricity 4 , it renders exciting potential to tune these 2D functionalities through strain or DW engineering utilizing the ferroelastic behavior.…”

Section: Discussionmentioning

confidence: 70%

Two-dimensional ferroelasticity in van der Waals β’-In2Se3

Mao

Guo

et al. 2021

Nat Commun

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Two-dimensional (2D) materials exhibit remarkable mechanical properties, enabling their applications as flexible and stretchable ultrathin devices. As the origin of several extraordinary mechanical behaviors, ferroelasticity has also been predicted theoretically in 2D materials, but so far lacks experimental validation and investigation. Here, we present the experimental demonstration of 2D ferroelasticity in both exfoliated and chemical-vapor-deposited β’-In2Se3 down to few-layer thickness. We identify quantitatively 2D spontaneous strain originating from in-plane antiferroelectric distortion, using both atomic-resolution electron microscopy and in situ X-ray diffraction. The symmetry-equivalent strain orientations give rise to three domain variants separated by 60° and 120° domain walls (DWs). Mechanical switching between these ferroelastic domains is achieved under ≤0.5% external strain, demonstrating the feasibility to tailor the antiferroelectric polar structure as well as DW patterns through mechanical stimuli. The detailed domain switching mechanism through both DW propagation and domain nucleation is unraveled, and the effects of 3D stacking on such 2D ferroelasticity are also discussed. The observed 2D ferroelasticity here should be widely available in 2D materials with anisotropic lattice distortion, including the 1T’ transition metal dichalcogenides with Peierls distortion and 2D ferroelectrics such as the SnTe family, rendering tantalizing potential to tune 2D functionalities through strain or DW engineering.

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Section: Discussionmentioning

confidence: 70%

Two-dimensional ferroelasticity in van der Waals β’-In2Se3

Mao

Guo

et al. 2021

Nat Commun

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“…WTe 2 is thermodynamically stable in the 1T ′ polymorph, while other TMDCs have been shown to be bi-stable. WSe 2 crystals, for instance, have been shown to exhibit coexisting crystalline domains of 1T ′ and 1H lattice structure, [166,167,171] the latter being a trivial insulator with a large electronic bandgap (1.9 eV). [166] This offers the tantalizing possibility to engineer [166] ordered and atomically abrupt 1T ′-2H crystal phase boundaries, whose interface can host 1D conducting boundary modes.…”

Section: T′-phase Transition Metal Dichalcogenides (Tmdcs)mentioning

confidence: 99%

“…[ 166 ] This offers the tantalizing possibility to engineer [ 166 ] ordered and atomically abrupt 1 T ′‐2H crystal phase boundaries, whose interface can host 1D conducting boundary modes. [ 166 ] Preliminary phase boundary engineering has already been demonstrated in 1 T ′/1H WSe 2 [ 171 ] and in other MX 2 materials. [ 172 ] A recent review by Li et al.…”

Section: Atomically Thin Qsh Materialsmentioning

confidence: 99%

Atomically Thin Quantum Spin Hall Insulators

et al. 2021

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Atomically thin topological materials are attracting growing attention for their potential to radically transform classical and quantum electronic device concepts. Among them is the quantum spin Hall (QSH) insulator—a 2D state of matter that arises from interplay of topological band inversion and strong spin–orbit coupling, with large tunable bulk bandgaps up to 800 meV and gapless, 1D edge states. Reviewing recent advances in materials science and engineering alongside theoretical description, the QSH materials library is surveyed with focus on the prospects for QSH‐based device applications. In particular, theoretical predictions of nontrivial superconducting pairing in the QSH state toward Majorana‐based topological quantum computing are discussed, which are the next frontier in QSH materials research.

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“…The properties of 2D TMDs are oen signicantly different from their bulk forms and can be ne-tuned for numerous applications. 14 Due to this versatility, TMDs are poised to play important roles in the elds of electronics, 15 optoelectronics, 16 electrochemical sensors 17 and catalysis, 18 to name but a few. One of the less-explored branches of TMD materials is noble-transition-metal dichalcogenides (NTMDs), 19 , (MX 2 : M ¼ Pt and Pd, and X ¼ S, Se and Te) which are predicted to exhibit different structural and electronic properties in comparison with well-studied MoS 2 .…”

Section: Introductionmentioning

confidence: 99%