Zhida Song
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View article: Moiré dependent Chern insulators in twisted crystalline flatbands
Moiré dependent Chern insulators in twisted crystalline flatbands Open
In moiré crystals, the competition between different isospin configurations can be tuned by twist angles and stacking orders, forming various symmetry-broken states. Here we report twisted double rhombohedral-trilayer-gaphene as a new twis…
View article: Cascade of Zero-field Chern Insulators in Magic-angle Bilayer Graphene
Cascade of Zero-field Chern Insulators in Magic-angle Bilayer Graphene Open
The interplay between strong electron-electron interactions and symmetry breaking can have a profound influence on the topological properties of materials. In magic-angle twisted bilayer graphene (MATBG), the flat band with a single SU(4) …
View article: Stable Real-Space Invariants and Topology Beyond Symmetry Indicators
Stable Real-Space Invariants and Topology Beyond Symmetry Indicators Open
We show that certain band gaps, which appear topologically trivial from the perspective of symmetry indicators (SIs), must instead be topological, as guaranteed by real-space information that follows from Topological Quantum Chemistry (TQC…
View article: Projected and Solvable Topological Heavy Fermion Model of Twisted Bilayer Graphene
Projected and Solvable Topological Heavy Fermion Model of Twisted Bilayer Graphene Open
We investigate the topological heavy-fermion (THF) model of magic-angle twisted bilayer graphene (MATBG) in the projected limit, where only the flat bands are present in the low-energy spectrum. Such limit has been previously analyzed in m…
View article: Hundness in twisted bilayer graphene: correlated gaps and pairing
Hundness in twisted bilayer graphene: correlated gaps and pairing Open
We characterize gap-opening mechanisms in the topological heavy fermion (THF) model of magic-angle twisted bilayer graphene (MATBG), with and without electron-phonon coupling, using dynamical mean-field theory (DMFT) with the numerical ren…
View article: Suppression of symmetry-breaking correlated insulators in a rhombohedral trilayer graphene superlattice
Suppression of symmetry-breaking correlated insulators in a rhombohedral trilayer graphene superlattice Open
Counterintuitive temperature dependence of isospin flavor polarization has recently been found in twisted bilayer graphene, where unpolarized electrons in a Fermi liquid become a spin-valley polarized insulator upon heating. So far, the ef…
View article: Correlated insulators and charge density wave states in chirally twisted triple bilayer graphene
Correlated insulators and charge density wave states in chirally twisted triple bilayer graphene Open
Motivated by recent experimental observations of displacement-field-tuned correlated insulators at integer and half-integer fillings in chirally twisted triple bilayer graphene (CTTBG) [Phys.Rev.Lett.132.246501], we study the single-partic…
View article: Spin Space Groups: Full Classification and Applications
Spin Space Groups: Full Classification and Applications Open
In this work, we exhaust all the spin space symmetries, which fully characterize collinear, noncollinear, and commensurate spiral as well as incommensurate spiral magnetism, etc., and investigate enriched features of electronic bands that …
View article: Commensurate and Incommensurate Chern Insulators in Magic-angle Bilayer Graphene
Commensurate and Incommensurate Chern Insulators in Magic-angle Bilayer Graphene Open
The interplay between strong electron-electron interaction and symmetry breaking can have profound influence on the topological properties of materials. In magic angle twisted bilayer graphene (MATBG), the flat band with a single SU(4) fla…
View article: Massive 1D Dirac Line, Solitons and Reversible Manipulation on the Surface of a Prototype Obstructed Atomic Insulator, Silicon
Massive 1D Dirac Line, Solitons and Reversible Manipulation on the Surface of a Prototype Obstructed Atomic Insulator, Silicon Open
Topologically trivial insulators can be classified into atomic insulators (AIs) and obstructed atomic insulators (OAIs) depending on whether the Wannier charge centers are localized or not at spatial positions occupied by atoms. An OAI can…
View article: Ring states in topological materials
Ring states in topological materials Open
Ingap states are commonly observed in semiconductors and are often well characterized by a hydrogenic model within the effective mass approximation. However, when impurities are strong, they significantly perturb all momentum eigenstates, …
View article: Tunable Fractional Chern Insulators in Rhombohedral Graphene Superlattices
Tunable Fractional Chern Insulators in Rhombohedral Graphene Superlattices Open
Fractional Chern insulators (FCIs) showing a transport effect with fractionally quantized Hall plateaus emerging under zero magnetic field, provide a radically new opportunity to engineer topological quantum electronics. By construction of…
View article: Correlated Charge Density Wave Insulators in Chirally Twisted Triple Bilayer Graphene
Correlated Charge Density Wave Insulators in Chirally Twisted Triple Bilayer Graphene Open
Electrons residing in flat-band system can play a vital role in triggering spectacular phenomenology due to relatively large interactions and spontaneous breaking of different degeneracies. In this work we demonstrate chirally twisted trip…
View article: Correlated insulators and charge density wave states in chirally twisted triple bilayer graphene
Correlated insulators and charge density wave states in chirally twisted triple bilayer graphene Open
Motivated by recent experimental observations of displacement-field-tuned correlated insulators at integer and half-integer fillings in chirally twisted triple bilayer graphene (CTTBG), we study the single-particle and interacting physics …
View article: Probing fragile topology with a screw dislocation
Probing fragile topology with a screw dislocation Open
Fragile topology, akin to twisted bilayer graphene and the exotic phases therein, is a notable topological class with intriguing properties. However, due to its unique nature and the lack of bulk-edge correspondence, the experimental signa…
View article: Filling-enforced obstructed atomic insulators
Filling-enforced obstructed atomic insulators Open
Topological band theory has achieved great success in the high-throughput search for topological band structures both in paramagnetic and magnetic crystal materials. However, a significant proportion of materials are topologically trivial …
View article: Author Correction: Interacting topological quantum chemistry in 2D with many-body real space invariants
Author Correction: Interacting topological quantum chemistry in 2D with many-body real space invariants Open
View article: Topological Heavy Fermion Principle For Flat (Narrow) Bands With Concentrated Quantum Geometry
Topological Heavy Fermion Principle For Flat (Narrow) Bands With Concentrated Quantum Geometry Open
We propose a general principle for the low-energy theory of narrow bands with concentrated Berry curvature and Fubini-Study metric in the form of a map to Anderson-"+" models composed of heavy fermions hybridizing and interacting with semi…
View article: Anderson critical metal phase in trivial states protected by average magnetic crystalline symmetry
Anderson critical metal phase in trivial states protected by average magnetic crystalline symmetry Open
View article: Evolution of flat band and role of lattice relaxations in twisted bilayer graphene
Evolution of flat band and role of lattice relaxations in twisted bilayer graphene Open
Magic-angle twisted bilayer graphene (MATBG) exhibits correlated phenomena such as superconductivity and Mott insulating state related to the weakly dispersing flat band near the Fermi energy. Beyond its moiré period, such flat band is exp…
View article: Berry curvature inside a <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mi mathvariant="script">PT</mml:mi></mml:math>-symmetry protected exceptional surface
Berry curvature inside a -symmetry protected exceptional surface Open
A three-dimensional non-Hermitian Hamiltonian with parity-time symmetry can exhibit a closed exceptional surface (EP surface) in momentum space, which is a non-Hermitian deformation of the degeneracy line. Since the degeneracy line lacks a…
View article: Interacting topological quantum chemistry in 2D with many-body real space invariants
Interacting topological quantum chemistry in 2D with many-body real space invariants Open
View article: Molecular Pairing in Twisted Bilayer Graphene Superconductivity
Molecular Pairing in Twisted Bilayer Graphene Superconductivity Open
We propose a theory for how the weak phonon-mediated interaction ($J_{\rm A}\!=\!1\!\sim\!4$meV) wins over the prohibitive Coulomb repulsion ($U\!=\!30\!\sim\!60$meV) and leads to a superconductor in magic-angle twisted bilayer graphene (M…
View article: Audio–Visual Fusion Based on Interactive Attention for Person Verification
Audio–Visual Fusion Based on Interactive Attention for Person Verification Open
With the rapid development of multimedia technology, personnel verification systems have become increasingly important in the security field and identity verification. However, unimodal verification systems have performance bottlenecks in …
View article: VASP2KP: kp models and Lande g-factors from ab initio calculations
VASP2KP: kp models and Lande g-factors from ab initio calculations Open
The $k\cdot p$ method is significant in condensed matter physics for the compact and analytical Hamiltonian. In the presence of magnetic field, it is described by the effective Zeeman's coupling Hamiltonian with Landé $ g $-factors. Here, …
View article: Spin Space Groups: Full Classification and Applications
Spin Space Groups: Full Classification and Applications Open
In this work, we exhaust all the spin-space symmetries, which fully characterize collinear, non-collinear, commensurate, and incommensurate spiral magnetism, and investigate enriched features of electronic bands that respect these symmetri…
View article: Interacting Topological Quantum Chemistry in 2D: Many-body Real Space Invariants
Interacting Topological Quantum Chemistry in 2D: Many-body Real Space Invariants Open
The topological phases of non-interacting fermions have been classified by their symmetries, culminating in a modern electronic band theory where wavefunction topology can be obtained from momentum space. Recently, Real Space Invariants (R…
View article: Anderson Critical Metal Phase in Trivial States Protected by Average Magnetic Crystalline Symmetry
Anderson Critical Metal Phase in Trivial States Protected by Average Magnetic Crystalline Symmetry Open
Transitions between distinct obstructed atomic insulators (OAIs) protected by crystalline symmetries, where electrons form molecular orbitals centering away from the atom positions, must go through an intermediate metallic phase. In this w…
View article: Twisted bilayer graphene as topological heavy fermion: II. Analytical approximations of the model parameters
Twisted bilayer graphene as topological heavy fermion: II. Analytical approximations of the model parameters Open
The recently-introduced topological heavy fermion (THF) model [1] of twisted bilayer graphene (TBG) aims to reconcile the quantum-dot-like electronic structure of the latter observed by scanning tunneling microscopy, with its electron delo…
View article: Massive 1D Dirac Line, Solitons and Reversible Manipulation on the Surface of a Prototype Obstructed Atomic Insulator, Silicon
Massive 1D Dirac Line, Solitons and Reversible Manipulation on the Surface of a Prototype Obstructed Atomic Insulator, Silicon Open
In the past decade, topological quantum materials have attracted enormous research efforts in both physics and materials science. However, despite increasing number of discovered topological quantum materials, recent high throughput comput…