arXiv subjects

Chuyi Tuo

Publications and source records attributed to Chuyi Tuo.

5 recordsLinked to original sources

arXiv2026

Chiral spin liquid and chiral antiferromagnetism in half-filled moir\'e Hubbard model: possible applications to twisted bilayer TMDs

Twisted transition metal dichalcogenides offer an exceptionally tunable moir\'e platform for studying correlation physics beyond conventional condensed matter systems. In particular, the intriguing interplay between the displacement field and the twist angle remains to be fully resolved. In this paper, we use large-scale density matrix renormalization group simulations to study the minimal moir\'e Hubbard model on a triangular lattice at half-filling, where the displacement field effect is captured by a spin-dependent staggered flux. We find that the displacement field significantly enriches the triangular Hubbard phase diagram in several qualitative ways. It rapidly destabilizes the chiral spin liquid phase beyond a narrow weak-field regime, induces pronounced chiral correlations in the strong-coupling $120^\circ$-antiferromagnetic phase, and stabilizes incommensurate spin-density wave phases at weaker coupling. We further find signatures of a continuous transition between the chiral spin liquid and chiral antiferromagnetic phases at a finite displacement field, potentially driven by spinon condensation. Our results uncover rich displacement-field-driven many-body physics and provide useful guidance for future experiments in moir\'e superlattice systems.

cond-mat.str-el↗

arXiv2025

Fractional quantum anomalous Hall and anyon density-wave halo in a minimal interacting lattice model of twisted bilayer MoTe$_2$

The experimental discovery of fractional quantum anomalous Hall (FQAH) states in tunable moir\'e superlattices has sparked intense interest in exploring the interplay between topological order and symmetry breaking phases. In this paper, we present a comprehensive numerical study of this interplay through large-scale density matrix renormalization group (DMRG) simulations on a minimal two-band lattice model of twisted bilayer MoTe$_2$ at filling $\nu=-2/3$. We find robust FQAH ground states and provide clear numerical evidences for anyon excitations with fractional charge and pronounced real-space density modulations, directly supporting the recently proposed anyon density-wave halo picture. We also map out the displacement field dependent phase diagram, uncovering a rich landscape of charge ordered states emerging from the FQAH, including a quantum anomalous Hall crystal (QAHC) with an integer quantized Hall conductance. We expect our work to inspire further research interest of intertwined correlated topological phases in moir\'e systems.

cond-mat.str-el↗

arXiv2025

Theory of Topological Superconductivity and Antiferromagnetic Correlated Insulators in Twisted Bilayer WSe$_2$

Since the very recent discovery of unconventional superconductivity in twisted WSe$_2$ homobilayers at filling $ν=-1$, considerable interest has arisen in revealing its mechanism. In this paper, we developed a three-band tight-binding model with non-trivial band topology by direct Wannierization of the low-energy continuum model. Incorporating both onsite Hubbard repulsion and next-nearest-neighbor attraction, we then performed a mean-field analysis of the microscopic model and obtained a phase diagram qualitatively consistent with the experiment results. For zero or weak displacement field, the ground state is a Chern number $C=\pm 2$ topological superconductor in the Altland-Zirnbauer A-class (breaking time-reversal but preserving total $S_z$ symmetry) with inter-valley pairing dominant in $d_{xy}\pm id_{x^2-y^2}$-wave (mixing with a subdominant $p_x\mp i p_y$-wave) component. For a relatively strong displacement field, the ground state is a correlated insulator with the $120^\circ$ antiferromagnetic order. Our results provide new insights into the nature of the twisted WSe$_2$ systems and suggest the need for further theoretical and experimental explorations.

cond-mat.str-el↗

arXiv2025

Single-band Triangular Lattice Hubbard Model with Tunable Anisotropy from Twisted Diamond Homobilayers

The ground-state properties of the single-band triangular lattice Hubbard model with hopping anisotropy and strong interactions remain elusive so far. Here we show that twisted diamond homobilayers with band extrema at $Y$ valley can realize weakly-coupled chains with quasi-1D band structure; applying displacement field generates interchain hopping, transforming this quasi-1D system into a 2D one. The low-energy physics can be described by localized Wannier functions on the triangular lattice with tunable hopping anisotropy, providing a promising platform for studying the anisotropic triangular lattice Hubbard model. We further employ density matrix renormalization group to study this model with interaction $U=10t$ and anisotropy $0.5\leq t'/t\leq 1.5$ at half filling, and obtain a rich ground state phase diagram, including a chiral spin liquid phase, non-magnetic phases, and a Néel antiferromagnetic phase. This work provides a first realization of displacement-field tuned anisotropy in a single-band triangular Hubbard model within moiré systems, establishing them as a promising platform to investigate intriguing correlated physics with tunable anisotropy.

cond-mat.str-el↗

arXiv2024

Correlated topological flat bands in rhombohedral graphite

Flat bands and nontrivial topological physics are two important topics of condensed matter physics. With a unique stacking configuration analogous to the Su-Schrieffer-Heeger (SSH) model, rhombohedral graphite (RG) is a potential candidate for realizing both flat bands and nontrivial topological physics. Here we report experimental evidence of topological flat bands (TFBs) on the surface of bulk RG, which are topologically protected by bulk helical Dirac nodal lines via the bulk-boundary correspondence. Moreover, upon {\it in situ} electron doping, the surface TFBs show a splitting with exotic doping evolution, with an order-of-magnitude increase in the bandwidth of the lower split band, and pinning of the upper band near the Fermi level. These experimental observations together with Hartree-Fock calculations suggest that correlation effects are important in this system. Our results demonstrate RG as a new platform for investigating the rich interplay between nontrivial band topology, correlation effects, and interaction-driven symmetry-broken states.

cond-mat.str-el↗