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We obtain the band structure of a particle moving in a magnetic spin texture, classified by its chirality and structure factor, in the presence of spin-orbit coupling. This rich interplay leads to a variety of novel topological phases…

Quantum Gases · Physics 2015-06-17 Timothy M. McCormick , Nandini Trivedi

Recent studies on topological flat bands and their fractional states have revealed increasing similarities between moir\'e flat bands and Landau levels (LLs). For instance, like the lowest LL, topological exact flat bands with ideal quantum…

Mesoscale and Nanoscale Physics · Physics 2025-08-11 Siddhartha Sarkar , Xiaohan Wan , Yitong Zhang , Kai Sun

The rapid advances in the study of fractional Chern insulators (FCIs) raise a fundamental question: while initially discovered in flat Chern bands motivated by their topological equivalence to Landau levels, is single- particle band…

Strongly Correlated Electrons · Physics 2025-10-17 Hongyu Lu , Wang Yao

With the inclusion of arbitrary long-range hopping and (pseudo)spin-orbit coupling amplitudes, we formulate a generic model that can describe any two-dimensional two-band bulk insulators, thus providing a simple framework to investigate…

Mesoscale and Nanoscale Physics · Physics 2021-03-03 Bo-Hung Chen , Dah-Wei Chiou

Two-dimensional 2-bands insulators breaking time reversal symmetry can present topological phases indexed by a topological invariant called the Chern number. Here we first propose an efficient procedure to determine this topological index.…

Mesoscale and Nanoscale Physics · Physics 2012-05-28 Doru Sticlet , Frederic Piéchon , Jean-Noël Fuchs , Pavel Kalugin , Pascal Simon

We propose a microscopic, weak-coupling mechanism by which generic Chern bands relax toward ideal bands. We consider coupling interacting electrons to a Caldeira-Leggett like Ohmic bosonic bath. Using the Born-Markov approximation, Slater…

Mesoscale and Nanoscale Physics · Physics 2025-11-17 Bruno Mera , Tomoki Ozawa

We present a theoretical study of mapping between Chern bands and generalized Landau levels in twisted bilayer MoTe$_2$ ($t$MoTe$_2$), where fractional Chern insulators down to zero magnetic fields have been observed. We construct an exact…

Mesoscale and Nanoscale Physics · Physics 2025-03-18 Bohao Li , Fengcheng Wu

We analyze a measurement scheme that allows determination of the Berry curvature and the topological Chern number of a Hamiltonian with parameters exploring a two-dimensional closed manifold. Our method uses continuous monitoring of the…

Quantum Physics · Physics 2017-07-12 Peng Xu , Alexander Holm Kiilerich , Ralf Blattmann , Yang Yu , Shi-Liang Zhu , Klaus Mølmer

We show that a quadratic form of quantum geometric tensor in $k$-space sets a bound on the $q^4$ term in the static structure factor $S(q)$ at small $\vec{q}$. Bands that saturate this bound satisfy a condition similar to Laplace's…

Mesoscale and Nanoscale Physics · Physics 2025-08-01 Yugo Onishi , Alexander Avdoshkin , Liang Fu

We present some formulae related to the Chern-Ricci curvatures and scalar curvatures of special Hermitian metrics. We prove that a compact locally conformal K\"{a}hler manifold with constant nonpositive holomorphic sectional curvature is…

Differential Geometry · Mathematics 2019-05-09 Haojie Chen , Lingling Chen , Xiaolan Nie

The Hofstadter model is a popular choice for theorists investigating the fractional quantum Hall effect on lattices, due to its simplicity, infinite selection of topological flat bands, and increasing applicability to real materials. In…

Strongly Correlated Electrons · Physics 2021-09-09 Bartholomew Andrews , Titus Neupert , Gunnar Möller

A singular flat band(SFB), a distinct class of the flat band, has been shown to exhibit various intriguing material properties characterized by a geometric quantity of the Bloch wave function called the quantum distance. We present a…

Strongly Correlated Electrons · Physics 2023-05-02 Hyeongseop Kim , Chang-geun Oh , Jun-Won Rhim

A long-standing conjecture in non-K\"ahler geometry states that if the Chern (or Levi-Civita) holomorphic sectional curvature of a compact Hermitian manifold is a constant $c$, then the metric must be K\"ahler when $c\neq 0$ and must be…

Differential Geometry · Mathematics 2026-03-17 Yulu Li , Fangyang Zheng

Topological flat bands at the Fermi level offer a promising platform to study a variety of intriguing correlated phase of matter. Here we present band engineering in the twisted orbital-active bilayers with spin-orbit coupling. The symmetry…

Mesoscale and Nanoscale Physics · Physics 2022-09-15 Huan Wang , Yadong Jiang , Zhaochen Liu , Jing Wang

Recent experimental discovery of fractional Chern insulators at zero magnetic field in moir\'e superlattices has sparked intense interests in bringing Landau level physics to flat Chern bands. In twisted MoTe$_2$ bilayers (tMoTe$_2$),…

Strongly Correlated Electrons · Physics 2025-02-25 Chong Wang , Xiao-Wei Zhang , Xiaoyu Liu , Jie Wang , Ting Cao , Di Xiao

The integer quantum Hall state occurs when the Landau levels are fully occupied by the fermions, while the fractional quantum Hall state usually emerges when the Landau level is partially filled by the strongly correlated fermions or…

Strongly Correlated Electrons · Physics 2021-09-22 Wei-Wei Luo , Ai-Lei He , Yi-Fei Wang , Yuan Zhou , Chang-De Gong

The Harper-Hofstadter model provides a fractal spectrum containing topological bands of any integer Chern number, $C$. We study the many-body physics that is realized by interacting particles occupying Harper-Hofstadter bands with $|C|>1$.…

Strongly Correlated Electrons · Physics 2015-09-28 Gunnar Möller , Nigel R. Cooper

A Chern insulator (quantum anomalous Hall insulator) phase is demonstrated to exist in a typical semi-Dirac system, the TiO2/VO2 heterostructure. By combining first-principles calculations with Wannier-based tight-binding model, we…

Materials Science · Physics 2015-11-04 Huaqing Huang , Zhirong Liu , Hongbin Zhang , Wenhui Duan , David Vanderbilt

We study the interplay between quantum Hall ordering and spontaneous sublattice symmetry breaking in multiple Chern number bands at fractional fillings. Primarily we study fermions with repulsive interactions near half filling in a family…

Strongly Correlated Electrons · Physics 2015-06-22 Akshay Kumar , Rahul Roy , S. L. Sondhi

The observation of zero field fractional quantum Hall analogs in twisted transition metal dichalcogenides (TMDs) asks for a deeper understanding of what mechanisms lead to topological flat bands in two-dimensional heterostructures, and what…

Mesoscale and Nanoscale Physics · Physics 2024-05-10 Valentin Crépel , Nicolas Regnault , Raquel Queiroz