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We show how the phases of interacting particles in topological flat bands, known as fractional Chern insulators, can be adiabatically connected to incompressible fractional quantum Hall liquids in the lowest Landau-level of an externally…

Mesoscale and Nanoscale Physics · Physics 2012-12-13 Thomas Scaffidi , Gunnar Moller

Non-Hermitian Chern insulators differ from their Hermitian cousins in one key aspect: their edge spectra are incredibly rich and confounding. For example, even in the simple case where the bulk spectrum consists of two bands with Chern…

Mesoscale and Nanoscale Physics · Physics 2023-01-05 James Bartlett , Erhai Zhao

Moir\'e flat bands in rhombohedral multilayer graphene provide a platform for exploring interaction-driven topological phases, where a single isolated band often forms a Chern band. However, non-Abelian degenerate Chern bands with internal…

Mesoscale and Nanoscale Physics · Physics 2026-04-16 Taketo Uchida , Takuto Kawakami , Mikito Koshino

We investigate topological band structures of a kagome system coupled to a circularly polarized cavity mode, using a model based on a muffin-tin potential and quantum light-matter interaction. We show that Chern insulating phases emerge in…

Mesoscale and Nanoscale Physics · Physics 2026-04-03 Hikaru Goto , Ryo Okugawa , Takami Tohyama

Chern insulators are band insulators exhibiting a nonzero Hall conductance but preserving the lattice translational symmetry. We conclusively show that a partially filled Chern insulator at 1/3 filling exhibits a fractional quantum Hall…

Strongly Correlated Electrons · Physics 2015-03-19 N. Regnault , B. Andrei Bernevig

When one of the graphene layers of Magic Angle Twisted Bilayer Graphene is nearly aligned with its hexagonal boron nitride substrate (a configuration dubbed TBG/hBN), the active electronic bands are nearly flat, and have a Chern number…

Strongly Correlated Electrons · Physics 2019-12-25 Cécile Repellin , T. Senthil

Narrow band electron systems are particularly likely to exhibit correlated many-body phases driven by interaction effects. Examples include magnetic materials, heavy fermion systems, and topological phases such as fractional quantum Hall…

Strongly Correlated Electrons · Physics 2016-07-19 Ching Hua Lee , Daniel P. Arovas , Ronny Thomale

Flatbands appear in many condensed matter systems, such as in high magnetic fields, correlated materials and moire heterostructures. They are characterized by intrinsic geometric properties such as the Berry curvature and Fubini-Study…

Mesoscale and Nanoscale Physics · Physics 2023-12-19 Jie Wang , Jennifer Cano , Andrew J. Millis , Zhao Liu , Bo Yang

We reveal a proximity effect between a topological band (Chern) insulator described by a Haldane model and spin-polarized Dirac particles of a graphene layer. Coupling weakly the two systems through a tunneling term in the bulk, the…

Mesoscale and Nanoscale Physics · Physics 2019-08-21 Peng Cheng , Philipp W. Klein , Kirill Plekhanov , Klaus Sengstock , Monika Aidelsburger , Christof Weitenberg , Karyn Le Hur

We propose a route towards creating a metamaterial that behaves as a photonic Chern insulator, through homogenization of an array of gyromagnetic cylinders. We show that such an array can exhibit non-trivial topological effects, including…

Optics · Physics 2017-10-04 Meng Xiao , Shanhui Fan

We present a scheme that allows integration of the Berry curvature and thus determination of the Chern number of a qubit eigenstate manifold. Our proposal continuously couples the qubit with a meter system while it explores a…

Quantum Physics · Physics 2020-09-16 Peng Xu , Shi-Liang Zhu , Klaus Mølmer , Alexander Holm Kiilerich

We uncover topological features of neutral particle-hole pair excitations of correlated quantum anomalous Hall (QAH) insulators whose approximately flat conduction and valence bands have equal and opposite non-zero Chern number. Using an…

Strongly Correlated Electrons · Physics 2021-04-02 Yves H. Kwan , Yichen Hu , Steven H. Simon , S. A. Parameswaran

The quantum geometric tensor (QGT) characterizes the complete geometric properties of quantum states, with the symmetric part being the quantum metric, and the antisymmetric part being the Berry curvature. We propose a generic Hamiltonian…

Quantum Physics · Physics 2024-04-22 Hai-Tao Ding , Chang-Xiao Zhang , Jing-Xin Liu , Jian-Te Wang , Dan-Wei Zhang , Shi-Liang Zhu

Lattice models forming bands with higher Chern number offer an intriguing possibility for new phases of matter with no analogue in continuum Landau levels. Here, we establish the existence of a number of new bulk insulating states at…

Strongly Correlated Electrons · Physics 2012-11-06 Zhao Liu , Emil J. Bergholtz , Heng Fan , Andreas M. Laeuchli

We generalize the concept of topological invariants for mixed states based on the ensemble geometric phase (EGP) introduced for one-dimensional lattice models to two dimensions. In contrast to the geometric phase for density matrices…

Quantum Physics · Physics 2021-09-22 Lukas Wawer , Michael Fleischhauer

We construct a continuum model for the Moir\'e superlattice of twisted bilayer MnBi$_2$Te$_4$, and study the band structure of the bilayer in both ferromagnetic (FM) and antiferromagnetic (AFM) phases. We find the system exhibits highly…

Mesoscale and Nanoscale Physics · Physics 2023-02-17 Biao Lian , Zhaochen Liu , Yuanbo Zhang , Jing Wang

The past few years have seen a revived interest in quantum geometrical characterizations of band structures due to the rapid development of topological insulators and semi-metals. Although the metric tensor has been connected to many…

Mesoscale and Nanoscale Physics · Physics 2023-03-07 Adrien Bouhon , Abigail Timmel , Robert-Jan Slager

The orbital magnetic susceptibility of an electron gas in a periodic potential depends not only on the zero field energy spectrum but also on the geometric structure of cell-periodic Bloch states which encodes interband effects. In addition…

Mesoscale and Nanoscale Physics · Physics 2016-10-26 Frédéric Piéchon , Arnaud Raoux , Jean-Noël Fuchs , Gilles Montambaux

We develop a technique for constructing Bloch-like functions for 2D Z_2-insulators (i.e., quantum spin-Hall insulators) that are smooth functions of k on the entire Brillouin-zone torus. As the initial step, the occupied subspace of the…

Mesoscale and Nanoscale Physics · Physics 2012-03-19 Alexey A. Soluyanov , David Vanderbilt

We study the formation and properties of perfectly-flat zero energy bands in a multi-layer graphene systems in the chiral limit. Employing the degrees of freedoms of the multi-layer system, such as relative twist-angle and relative shifts,…

Mesoscale and Nanoscale Physics · Physics 2024-04-25 Roi Makov , Francisco Guinea , Ady Stern