Evidence for higher order topology in Bi and Bi0.92Sb0.08

Aggarwal, Leena; Zhu, Penghao; Hughes, Taylor L.; Madhavan, Vidya

doi:10.1038/s41467-021-24683-8

Cited by 61 publications

(33 citation statements)

References 27 publications

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“…Since their initial discovery, HOTSC and their descendants have been discussed extensively and have become an active area of theoretical and experiential research. Recent progress has included topological classifications [3][4][5][6][7][8], topological field theories [8,9], and experimental realization of various classes of HOTSC [10][11][12][13][14][15][16][17][18][19].…”

Section: Introductionmentioning

confidence: 99%

Anomalous flux state in higher-order topological superconductors

You¹

2023

Preprint

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We investigate the anomalous flux state of interacting higher-order topological superconductors (HOTSC) protected by rotation symmetries. By introducing a π superconducting flux in 2D HOTSC, we demonstrate the existence of a robust zero mode trapped at the flux center. Remarkably, the rotation symmetry and fermion parity display projective representation inside the π flux with N = 2 supersymmetry algebra. A similar gapless flux pattern also exists in 3D HOTSCs, the flux lines of which carry anomalous helical modes that cannot be realized on purely one-dimensional lattice models. Notably, these exotic phenomena can be manifested in a 2D frustrated quantum magnet whose low energy excitation characterizes emergent Majoranas with HOTSC band structure and the Z2 flux exhibiting supersymmetries.

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Section: Introductionmentioning

confidence: 99%

Anomalous flux state in higher-order topological superconductors

You¹

2023

Preprint

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“…Since their initial discovery, HOSPTs have attracted a great deal of attention from both the theoretical and experimental communities. Recent progress includes symmetry classifications [3][4][5][6][7][8], topological field theory descriptions [8][9][10][11], and experimental realizations of various classes of HOSPTs [12][13][14][15][16][17][18][19][20][21]. Despite the success in non-interacting HOSPTs, i.e., band insulators and meanfield superconductors, the study of strongly interacting HOSPTs is still in an early stage.…”

Section: Introductionmentioning

confidence: 99%

Interaction Enabled Fractonic Higher-Order Topological Phases

May-Mann,

You,

Hughes

et al. 2022

Preprint

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In this work, we present a collection of three-dimensional higher-order symmetry protected topological phases (HOSPTs) with gapless hinge modes that exist only in strongly interacting systems subject to subsystem symmetry constraints. We use a coupled wire construction to generate three families of microscopic lattice models: insulators with helical hinge modes, superconductors with chiral Majorana hinge modes, and fractionalized insulators with helical hinge modes that carry fractional charge. In particular, these HOSPTs do not require spatial symmetry protection, but are instead protected by subsystem symmetries, and support "fractonic" quasiparticle excitations that move within only a low-dimensional sub-manifold of the system. We analyze the anomaly structure for the boundary theory and the entanglement Hamiltonian, and show that the side surfaces of these HOSPTs, despite being partially gapped, exhibit symmetry anomalies, and can only be realized as the boundary of three-dimensional HOSPT phases.

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“…In spite of their theoretical predictions in several 2D materials, − e.g. , graphyne, graphdiyne, , or twisted bilayer graphene, − higher-order TIs have been experimentally characterized to date in electronic systems limited to 3D materials, − which calls for the further exploration of material candidates for 2D higher-order TIs.…”

Section: Introductionmentioning

confidence: 99%

Organic Higher-Order Topological Insulators: Heterotriangulene-Based Covalent Organic Frameworks

Huang

Brédas

2022

J. Am. Chem. Soc.

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The ability to design and control the chemical characteristics of covalent organic frameworks (COFs) offers a new avenue for the development of functional materials, especially with respect to topological properties. Based on density functional theory calculations, by varying the core units through the choice of bridging groups [O, CO, CH2, or C(CH3)2] and the linker units [acetylene, diacetylene, or benzene], we have designed heterotriangulene-based COFs that are predicted to be two-dimensional higher-order topological insulators (TIs). The higher-order TI characteristics of these COFs are identified via their topological invariants and the presence of in-gap topological corner modes and gapped edge states. The frontier molecular orbital energies of the building moieties play an important role in determining the size of the higher-order TI gap, which we find to be highly dependent on linker units. We also examined the deposition of the COFs on a boron nitride substrate to assess the feasibility of experimental observation of a higher-order TI phase in the organic layer. This work thus provides new insights into heterotriangulene-based COFs and guidance for the exploration of purely organic topological materials.

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Evidence for higher order topology in Bi and Bi0.92Sb0.08

Cited by 61 publications

References 27 publications

Anomalous flux state in higher-order topological superconductors

Anomalous flux state in higher-order topological superconductors

Interaction Enabled Fractonic Higher-Order Topological Phases

Organic Higher-Order Topological Insulators: Heterotriangulene-Based Covalent Organic Frameworks

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