arXiv subjects

Jianqi Zhong

Publications and source records attributed to Jianqi Zhong.

4 recordsLinked to original sources

arXiv2026

Floquet Topological Spin-Valley-Layertronics on a Layered Dice Lattice

The recent discovery of long-sought dice flat band in layered YCl electride has opened up rich possibilities of correlation and topological physics in dice lattice systems [Nature Communications 17, 2213 (2026), arXiv:2509.05958]. Here, we reveal a plethora of distinctive correlated topological phases in a generic layered dice lattice system at band filling of $ν=4$ under on-site Hubbard interactions: (i) the system is an intrinsic sublattice anti-ferromagnetic (AFM) quantum spin-valley Hall insulator; (ii) a circularly polarized light (CPL) drives the AFM spin-valley insulator into a Floquet odd-parity $f$-wave altermagnet(AM) insulator; (iii) a vertical displacement field turns the Floquet $f$-wave AM insulator into a spin-valley-layer-polarized Chern insulator, with the sign of spin, valley and Chern number all controlled by the direction of the displacement field. Our results not only establish the layered dice lattice as a versatile platform for electrically switchable magnetic and topological phases, but also provide an all-electrical scheme for integrated spin-valley-layertronics for non-volatile information storage and processing.

cond-mat.mtrl-sci↗

arXiv2026

Entwined lattice of atoms and anionic electrons in layered electride LaCl

Controlling the lattice geometry that governs electronic structure is a central theme in condensed-matter physics, yet in crystalline solids this geometry is usually fixed by the atomic framework. Electrides offer an alternative route to electronic structure design in which their excess electrons can organize into anionic electron lattice (AEL) and provide a lattice-like degree of freedom. Recent work has highlighted the standalone limit, where the AEL in YCl yields bands well described by the dice-lattice model. Here, using angle-resolved photoemission spectroscopy (ARPES), we show that LaCl, although isostructural to YCl, realizes a qualitatively different regime where the AEL is entwined with the La cation framework, producing a fully reconstructed electronic structure. Combining the ARPES result with tight-binding model analysis, we demonstrate that this radical divergence stems from the activation of direct hopping channels between the AEL and the La atomic lattice. This coupling reshapes the effective lattice geometry, reconstructs the electronic states, and modifies the associated Chern band topology, transforming the bipartite dice-lattice network in YCl into a tripartite structure in LaCl. Our findings demonstrate that the coupling between the AEL and the atomic lattice can actively shape the effective lattice geometry that governs the electronic structure. This coupling can act as a powerful tuning knob for electronic structure design that is inaccessible in conventional materials.

cond-mat.str-el↗

arXiv2026

YCl Electride as a Multi-Orbital Correlated Topological Dice Lattice System

The long-sought dice lattice flat band has recently been discovered for the first time in two-dimensional layered electride yttrium monochloride (YCl) [Nature Communications 17, 2213 (2026)]. While essential flat band features of YCl were captured by an idealized simple dice lattice model, we reveal in this Letter that a unique layer-orbital-valley coupling in YCl puts up a fundamental obstruction against a simple three-band dice lattice description of the flat band, and necessitates a multi-orbital description that faithfully represents the symmetry, topology, and correlation physics in the first-ever dice metal. Using an ab initio based multi-orbital Hubbard model with local interactions, we predict that the multi-orbital flat band supports a robust ferromagnetic ground state and electrically tunable correlated quantum anomalous Hall phases that are absent in an interacting single-orbital dice lattice. Our findings open a new avenue for exploring correlation and topology in electride systems.

cond-mat.mtrl-sci↗

arXiv2025

5d orbital Induced Room Temperature Quantum Anomalous Hall Effect in TbCl

Following the experimental realization of Quantum anomalous Hall (QAH) effect in thin films of chromium-doped (Bi,Sb)$_2$Te$_3$, enhancing the work temperature of QAH effect has emerged as a significant and challenging task. Here we demonstrate monolayer TbCl as a promising candidate to realize the room temperature QAH effect. Using DFT+U method, double checked by HSE06 and DMFT calculations, we identify the Hall conductivity $G = -e^2/h$ per layer in three-dimensional ferromagnetic insulator TbCl, which is a weakly stacking of QAH layers. The monolayer TbCl inherits the magnetic and topological properties, exhibiting the QAH effect with Chern number $C$=-1. The large topological band gap reaches 42.8 meV, which is beyond room temperatue. The extended 5$d$ electrons lead to sizable exchange and superexchange interactions, resulting in a high Curie temperature $T_c$$\sim$457K. All these features demonstrate that monolayer TbCl will provide an ideal platform to realize the room temperature QAH effect.

cond-mat.mtrl-sci↗