Quantum anomalous Hall effect in time-reversal-symmetry breaking topological insulators

Chang, Cui Zu; Li, Mingda

doi:10.1088/0953-8984/28/12/123002

Cited by 104 publications

(91 citation statements)

References 112 publications

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“…There, up and down spin electrons exhibit helical quantum Hall effects in graphene, and backscattering terms are forbidden due to TR invariance. [44] The band structure of a ZGNR with KM interaction shows that there are two bands which traverse the bulk gap, connecting the K and K 0 points. These bands are localized edge states.…”

Section: Kane-mele (Intrinsic) Spin-orbital Interactionmentioning

confidence: 99%

Non‐Centrosymmetric Superconductors on Honeycomb Lattice

Lee

Chung

2018

Physica Status Solidi (b)

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Non-centrosymmetric topological superconductivity is studied in correlated doped quantum spin-Hall insulators (QSHI) on honeycomb lattice without inversion symmetry where the intrinsic (Kane-Mele) and Rashba spin-orbit couplings can in general exist. The generic topologically non-trivial superconducting phase diagram of the model system is explored. Over a certain parameter range, the parity-mixing superconducting state with co-existing spin-singlet d þ id and spin-triplet p þ ip-wave pairing is found. On a zigzag nanoribbon, the parity-mixing superconducting state shows co-existing helical and chiral Majorana fermions at edges. The relevance of our results for experiments is discussed.

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Section: Kane-mele (Intrinsic) Spin-orbital Interactionmentioning

confidence: 99%

Non‐Centrosymmetric Superconductors on Honeycomb Lattice

Lee

Chung

2018

Physica Status Solidi (b)

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“…This 2D magnetic TI shows a quantum anomalous Hall effect and has been intensively investigated [48][49][50]. These can now be experimentally realized by introducing magnetic doping with Cr, V, or Mn ions [51][52][53][54][55][56][57], or inducing proximity-induced ferromagnetism with a ferromagnetic insulator (FI) (i.e., TI/FI heterostructure) [57,58] to TI. Moreover, chiral MZMs are currently experimentally observed in a magnetic TI through the proximity effect to a conventional s-wave superconductor [24].…”

Section: Introductionmentioning

confidence: 99%

Majorana corner states in a two-dimensional magnetic topological insulator on a high-temperature superconductor

2018

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Conventional n-dimensional topological superconductors (TSCs) have protected gapless (n − 1)dimensional boundary states. In contrast to this, second-order TSCs are characterized by topologically protected gapless (n − 2)-dimensional states with usual gapped (n − 1)-boundaries.Here, we study a second-order TSC with a two-dimensional (2D) magnetic topological insulator (TI) proximity-coupled to a high-temperature superconductor, where Majorana bound states (MBSs) are localized at the corners of a square sample with gapped edge modes. Due to the mirror symmetry of the hybrid system considered here, there are two MBSs at each corner for both cases: d-wave and s±-wave superconducting pairing. We present the corresponding topological phase diagrams related to the role of the magnetic exchange interaction and the pairing amplitude. A detailed analysis, based on edge theory, reveals the origin of the existence of MBSs at the corners of the 2D sample, which results from the sign change of the Dirac mass emerging at the intersection of any two adjacent edges due to pairing symmetry. Possible experimental realizations are discussed. Our proposal offers a promising platform for realizing MBSs and performing possible non-Abelian braiding in 2D systems. arXiv:1806.07002v2 [cond-mat.mes-hall]

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“…In particular the discovery of the quantum anomalous Hall effect (QAHE) [5] led to intense research activities in magnetically doped TIs. To date, the observation of the QAHE was only successful at low temperatures with bulk-doped samples [6]. However, the mechanism for a robust realization of the QAHE phase in magnetically doped TIs is still unclear, despite numerous research efforts on magnetically doped topological insulators .…”

Section: Introductionmentioning

confidence: 99%

Towards microscopic control of the magnetic exchange coupling at the surface of a topological insulator

et al. 2018

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Magnetically doped topological insulators may produce novel states of electronic matter, where for instance the quantum anomalous Hall effect state can be realized. Pivotal to this goal is a microscopic control over the magnetic state, defined by the local electronic structure of the dopants and their interactions. We report on the magnetic coupling among Mn or Co atoms adsorbed on the surface of the topological insulator Bi 2 Te 3 . Our findings uncover the mechanisms of the exchange coupling between magnetic atoms coupled to the topological surface state in strong topological insulators. The combination of x-ray magnetic circular dichroism and ab initio calculations reveals that the sign of the magnetic coupling at short adatom-adatom distances is opposite for Mn with respect to Co. For both elements, the magnetic exchange reverses its sign at a critical distance between magnetic adatoms, as a result of the interplay between superexchange, double exchange and Ruderman-Kittel-Kasuya-Yoshida interactions.

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Quantum anomalous Hall effect in time-reversal-symmetry breaking topological insulators

Cited by 104 publications

References 112 publications

Non‐Centrosymmetric Superconductors on Honeycomb Lattice

Non‐Centrosymmetric Superconductors on Honeycomb Lattice

Majorana corner states in a two-dimensional magnetic topological insulator on a high-temperature superconductor

Towards microscopic control of the magnetic exchange coupling at the surface of a topological insulator

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