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Related papers: Evidence for a Monolayer Excitonic Insulator

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The quantum spin Hall (QSH) state was recently demonstrated in monolayers of the transition metal dichalcogenide 1T'-WTe$_2$ and is characterized by a band gap in the two-dimensional (2D) interior and helical one-dimensional (1D) edge…

Two-dimensional (2D) topological insulators (TIs) with a large bulk band-gap are promising for experimental studies of the quantum spin Hall effect and for spintronic device applications. Despite considerable theoretical efforts in…

Quantum spin Hall (QSH) insulators are a topologically protected phase of matter in two dimensions that can support non-dissipative spin transport. A hallmark of the phase is a pair of helical edge states surrounding an insulating bulk. A…

Mesoscale and Nanoscale Physics · Physics 2024-02-07 Kaifei Kang , Yichen Qiu , Kenji Watanabe , Takashi Taniguchi , Jie Shan , Kin Fai Mak

Discovering materials that combine topological phenomena with correlated electron behavior is a central pursuit in quantum materials research. Monolayer TaIrTe$_4$ has recently emerged as a promising platform in this context, hosting robust…

The fundamental idea of the excitonic insulator (EI) driven by electron-hole correlations in narrow-gap semiconductors or semimetals was originally proposed in the 1960s, and only theoretical studies had been advanced for a long time.…

Strongly Correlated Electrons · Physics 2024-12-25 Tatsuya Kaneko , Yukinori Ohta

Two-dimensional (2D) topological insulators (TIs) are promising platforms for low-dissipation spintronic devices based on the quantum spin Hall (QSH) effect, but experimental realization of such systems with a large band gap suitable for…

Mesoscale and Nanoscale Physics · Physics 2018-05-23 P. Chen , W. -W. Pai , Y. -H. Chan , W. -L. Sun , C. -Z. Xu , D. -S. Lin , M. Y. Chou , A. -V. Fedorov , T. -C. Chiang

We investigate the ground state of a balanced electron-hole system in the quantum Hall regime using mean-field theory and obtain a rich phase diagram as a function of interlayer distance d and the filling factor within a layer. We identify…

Mesoscale and Nanoscale Physics · Physics 2007-12-03 C. -H. Zhang , Yogesh N. Joglekar

We explore the emergence of topological phases in moir\'{e} MoTe$_2$/WSe$_2$ bilayer, highlighting the crucial role of spin-orbit coupling and Coulomb interactions at two holes per moir\'e unit cell \(v = 2\). Our analysis uncovers robust…

Mesoscale and Nanoscale Physics · Physics 2026-04-24 Palash Saha , Michał Zegrodnik

Quantum spin Hall (QSH) insulators exhibit spin-polarized conducting edge states that are topologically protected from backscattering and offer unique opportunities for addressing fundamental science questions and device applications.…

Mesoscale and Nanoscale Physics · Physics 2026-01-14 Rajibul Islam , Rahul Verma , Barun Ghosh , Zahir Muhammad , Arun Bansil , Carmine Autieri , Bahadur Singh

Evidence for the quantum spin Hall (QSH) effect has been reported in several experimental systems in the form of approximately quantized edge conductance. However, the most fundamental feature of the QSH effect, spin-momentum locking in the…

Topological phases, especially topological crystalline insulators (TCIs), have been intensively explored observed experimentally in three-dimensional (3D) materials. However, the two-dimensional (2D) films are explored much less than 3D…

Materials Science · Physics 2017-11-22 Yi-zhen Jia , Wei-xiao Ji , Chang-wen Zhang , Ping Li , Shu-feng Zhang , Pei-ji Wang , Sheng-shi Li , Shi-shen Yan

Analogous to the charged electron-electron pair condensation in superconductors, an excitonic insulator (EI) represents Fermi surface instability due to spontaneous formation and condensation of charge-neutral electron-hole pair (exciton).…

Strongly Correlated Electrons · Physics 2024-05-28 R. Okuma , K. Yamagami , Y. Fujisawa , C. H. Hsu , Y. Obata , N. Tomoda , M. Dronova , K. Kuroda , H. Ishikawa , K. Kawaguchi , K. Aido , K. Kindo , Y. H. Chan , H. Lin , Y. Ihara , T. Kondo , Y. Okada

Topological insulators (TIs) are promising for achieving dissipationless transport devices due to the robust gapless states inside the insulating bulk gap. However, currently realized 2D TIs, quantum spin Hall (QSH) insulators, suffer from…

Recently, quantum oscillation of the resistance in insulating monolayer WTe$_2$ was reported. An explanation in terms of gap modulation in the hybridized Landau levels of an excitonic insulator was also proposed by one of us. However, the…

Mesoscale and Nanoscale Physics · Physics 2021-07-27 Wen-Yu He , Patrick A. Lee

Topological insulating states in two-dimensional (2D) materials are ideal systems to study different types of quantized response signals due to their in gap metallic states. Very recently, the quantum spin Hall (QSH) effect was discovered…

Mesoscale and Nanoscale Physics · Physics 2024-04-23 Junwen Lai , Xiangyang Liu , Jie Zhan , Tianye Yu , Peitao Liu , Xing-Qiu Chen , Yan Sun

Meeting of non-trivial topology with magnetism results in novel phases of matter, such as Quantum Anomalous Hall (QAH) or axion insulator phases. Even more exotic states with high and tunable Chern numbers are expected at the contact of…

The quantum spin Hall (QSH) effect, characterized by topologically protected spin-polarized edge states, was recently demonstrated in monolayers of the transition metal dichalcogenide (TMD) WTe$_2$. However, the robustness of this…

Mesoscale and Nanoscale Physics · Physics 2024-05-07 Felix Lüpke , Dacen Waters , Anh D. Pham , Jiaqiang Yan , David G. Mandrus , Panchapakesan Ganesh , Benjamin M. Hunt

Two-dimensional topological insulators (2DTIs), which host the quantum spin Hall (QSH) effect, are one of the key materials in next-generation spintronic devices. To date, experimental evidence of the QSH effect has only been observed in a…

We study by a consistent mean-field scheme the role on the single- and two-particle properties of a local electron-electron repulsion in the Bernevig, Hughes and Zhang model of a quantum spin Hall insulator. We find that the interaction…

Strongly Correlated Electrons · Physics 2020-07-29 A. Blason , M. Fabrizio

Topological crystalline insulators (TCIs) host topological phases of matter protected by crystal symmetries. Topological surface states in three-dimensional TCIs have been predicted and observed in IV-VI SnTe-class semiconductors. Despite…

Mesoscale and Nanoscale Physics · Physics 2026-01-30 Liwei Jing , Mohammad Amini , Adolfo O. Fumega , Orlando J. Silveira , Jose L. Lado , Peter Liljeroth , Shawulienu Kezilebieke