Nicolas Regnault
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View article: New magnetic topological materials from high-throughput search
New magnetic topological materials from high-throughput search Open
We conducted a high-throughput search for topological magnetic materials across 522 new, experimentally reported commensurate magnetic structures from MAGNDATA, doubling the number of available materials on the Topological Magnetic Materia…
View article: Chern-Selective multi-valley Flat Bands in Twisted Mono-Bilayer and Mono-Trilayer MoTe$_2$
Chern-Selective multi-valley Flat Bands in Twisted Mono-Bilayer and Mono-Trilayer MoTe$_2$ Open
The interplay between moiré flat bands originating from different valleys can give rise to a variety of exotic quantum phases. In this work, we investigate the electronic properties of twisted mono-bilayer (A-AB) and mono-trilayer (A-ABA) …
View article: Obtaining the Spectral Function of Moiré Graphene Heavy-Fermions Using Iterative Perturbation Theory
Obtaining the Spectral Function of Moiré Graphene Heavy-Fermions Using Iterative Perturbation Theory Open
The spectral functions of twisted bilayer graphene (TBG) in the absence of strain have recently been investigated in both the symmetric and symmetry-broken phases using dynamical mean-field theory (DMFT). The theoretically predicted Mott-H…
View article: Critical Majorana fermion at a topological quantum Hall bilayer transition
Critical Majorana fermion at a topological quantum Hall bilayer transition Open
Quantum Hall bilayers are a uniquely tunable platform that can realize continuous transitions between distinct topological phases of matter. One prominent example is the transition between the Halperin state and the Moore--Read Pfaffian, l…
View article: Symmetry Resolved Entanglement Entropy in a Non-Abelian Fractional Quantum Hall State
Symmetry Resolved Entanglement Entropy in a Non-Abelian Fractional Quantum Hall State Open
Symmetry-resolved entanglement entropy provides a powerful framework for probing the internal structure of quantum many-body states by decomposing entanglement into contributions from distinct symmetry sectors. In this work, we apply matri…
View article: Multiband exact diagonalization and an iteration approach to search for fractional Chern insulators in rhombohedral multilayer graphene
Multiband exact diagonalization and an iteration approach to search for fractional Chern insulators in rhombohedral multilayer graphene Open
We perform a multi-band exact diagonalization (ED) study of rhombohedral pentalayer graphene twisted on hexagonal boron nitride with a focus on fractional Chern insulators (FCI) in systems with weak moiré gaps, complementing the results of…
View article: Spinless and spinful charge excitations in moiré Fractional Chern Insulators
Spinless and spinful charge excitations in moiré Fractional Chern Insulators Open
Fractionally charged elementary excitations, the quasi-electron and quasi-hole, are one of the hallmarks of the fractional Chern insulator (FCI). In this work, we observe that spontaneous spin polarization in twisted MoTe$_2$ leads to mult…
View article: Topologically Protected Flatness in Chiral Moiré Heterostructures
Topologically Protected Flatness in Chiral Moiré Heterostructures Open
The observation of delicate correlated phases in twisted heterostructures of graphene and transition metal dichalcogenides suggests that moiré flat bands are intrinsically resilient against certain types of disorder. Here, we investigate t…
View article: Tunable vacuum-field control of fractional and integer quantum Hall phases
Tunable vacuum-field control of fractional and integer quantum Hall phases Open
In quantum mechanics, empty space is not void but is characterized by vacuum-field fluctuations, which underlie phenomena such as the Lamb shift 1 , spontaneous emission, and the Casimir effect 2 . Due to their quantitatively small relativ…
View article: Observation of High-Temperature Dissipationless Fractional Chern Insulator
Observation of High-Temperature Dissipationless Fractional Chern Insulator Open
The fractional quantum anomalous Hall effect has recently been experimentally observed in zero-field fractional Chern insulators (FCI). However, an outstanding challenge is the presence of a substantial longitudinal resistance $R_{xx}$ (a …
View article: Fractional topological states in rhombohedral multilayer graphene modulated by kagome superlattice
Fractional topological states in rhombohedral multilayer graphene modulated by kagome superlattice Open
Fractional quantum anomalous Hall effects realized in twisted bilayer MoTe$_2$ and multilayer-graphene-based moiré heterostructures have captured a tremendous growth of interest. In this work, we propose that rhombohedral multilayer graphe…
View article: Kekulé Spiral Order from Strained Topological Heavy Fermions
Kekulé Spiral Order from Strained Topological Heavy Fermions Open
The topological heavy fermion (THF) model of twisted bilayer graphene is a framework for treating its strongly interacting topological flat bands. In this work, we employ the THF model with heterostrain and particle-hole symmetry breaking …
View article: Regularizing 3D conformal field theories via anyons on the fuzzy sphere
Regularizing 3D conformal field theories via anyons on the fuzzy sphere Open
Recently introduced ''fuzzy sphere'' method has enabled accurate numerical regularizations of certain three-dimensional (3D) conformal field theories (CFTs). The regularization is provided by the non-commutative geometry of the lowest Land…
View article: 2D Theoretically Twistable Material Database
2D Theoretically Twistable Material Database Open
The study of twisted two-dimensional (2D) materials, where twisting layers create moiré superlattices, has opened new opportunities for investigating topological phases and strongly correlated physics. While systems such as twisted bilayer…
View article: Two-dimensional Topological Quantum Chemistry and Catalog of Topological Materials
Two-dimensional Topological Quantum Chemistry and Catalog of Topological Materials Open
We adapt the topological quantum chemistry formalism to layer groups, and apply it to study the band topology of 8,872 entries from the computational two-dimensional (2D) materials databases C2DB and MC2D. In our analysis, we find 4,073 to…
View article: Universal Moiré-Model-Building Method without Fitting: Application to Twisted MoTe$_2$ and WSe$_2$
Universal Moiré-Model-Building Method without Fitting: Application to Twisted MoTe$_2$ and WSe$_2$ Open
We develop a comprehensive method to construct analytical continuum models for moiré systems directly from first-principle calculations without any parameter fitting. The core idea of this method is to interpret the terms in the continuum …
View article: Fractional quantum Hall phases in high-mobility n-type molybdenum disulfide transistors
Fractional quantum Hall phases in high-mobility n-type molybdenum disulfide transistors Open
Transistors based on semiconducting transition metal dichalcogenides can, in theory, offer high carrier mobilities, strong spin–orbit coupling and inherently strong electronic interactions at the quantum ground states. This makes them well…
View article: New magnetic topological materials from high-throughput search
New magnetic topological materials from high-throughput search Open
We conducted a high-throughput search for topological magnetic materials on 522 new, experimentally reported commensurate magnetic structures from MAGNDATA, doubling the number of available materials on the Topological Magnetic Materials d…
View article: Fingerprints of composite fermion Lambda levels in scanning tunneling microscopy
Fingerprints of composite fermion Lambda levels in scanning tunneling microscopy Open
A composite fermion (CF) is a topological quasiparticle that emerges from a nonperturbative attachment of vortices to electrons in strongly correlated two-dimensional materials. Similar to noninteracting fermions that form Landau levels in…
View article: Moiré Fractional Chern Insulators IV: Fluctuation-Driven Collapse of FCIs in Multi-Band Exact Diagonalization Calculations on Rhombohedral Graphene
Moiré Fractional Chern Insulators IV: Fluctuation-Driven Collapse of FCIs in Multi-Band Exact Diagonalization Calculations on Rhombohedral Graphene Open
The fractional Chern insulators (FCIs) observed in pentalayer rhombohedral graphene/hexagonal boron nitride superlattices have a unique origin contrary to theoretical expectations: their non-interacting band structure is gapless, unlike st…
View article: When Could Abelian Fractional Topological Insulators Exist in Twisted MoTe$_2$ (and Other Systems)
When Could Abelian Fractional Topological Insulators Exist in Twisted MoTe$_2$ (and Other Systems) Open
Using comprehensive exact diagonalization calculations on $θ\approx 3.7 ^{\circ}$ twisted bilayer MoTe$_2$ ($t$MoTe$_2$), as well as idealized Landau level models also relevant for lower $θ$, we extract general principles for engineering f…
View article: Ferromagnetism and Topology of the Higher Flat Band in a Fractional Chern Insulator
Ferromagnetism and Topology of the Higher Flat Band in a Fractional Chern Insulator Open
The recent observation of the fractional quantum anomalous Hall effect in moiré fractional Chern insulators provides an opportunity to investigate zero magnetic field anyons. To potentially realize non-Abelian anyons, one approach is to en…
View article: Enhanced fractional quantum Hall gaps in a two-dimensional electron gas coupled to a hovering split-ring resonator
Enhanced fractional quantum Hall gaps in a two-dimensional electron gas coupled to a hovering split-ring resonator Open
The magnetotransport of a high-mobility two-dimensional electron gas coupled to a hovering split-ring resonator with controllable distance is studied in the quantum Hall regime. The measurements reveal an enhancement by more than a factor …
View article: Heavy Fermions as an Efficient Representation of Atomistic Strain and Relaxation in Twisted Bilayer Graphene
Heavy Fermions as an Efficient Representation of Atomistic Strain and Relaxation in Twisted Bilayer Graphene Open
Although the strongly interacting flat bands in twisted bilayer graphene (TBG) have been approached using the minimal Bistritzer-MacDonald (BM) Hamiltonian, there is mounting evidence that strain and lattice relaxation are essential in cor…
View article: Moiré fractional Chern insulators. II. First-principles calculations and continuum models of rhombohedral graphene superlattices
Moiré fractional Chern insulators. II. First-principles calculations and continuum models of rhombohedral graphene superlattices Open
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View article: Fractional quantum Hall effect of partons and the nature of the 8/17 state in the zeroth Landau level of bilayer graphene
Fractional quantum Hall effect of partons and the nature of the 8/17 state in the zeroth Landau level of bilayer graphene Open
We consider the fractional quantum Hall effect (FQHE) at the filling factor $8/17$, where signatures of incompressibility have been observed in the zeroth Landau level of bilayer graphene. We propose an Abelian state described by the ``$\o…
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: 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: Topologically protected flatness in chiral moiré heterostructures
Topologically protected flatness in chiral moiré heterostructures Open
The observation of delicate correlated phases in twisted heterostructures of graphene and transition metal dichalcogenides suggests that moiré flat bands are intrinsically resilient against certain types of disorder. Here, we investigate t…