Research direction 02

Electrons

Topology · correlation · superconductivity

I connect first-principles materials discovery to interaction-driven topology, superconductivity, and quantum devices through symmetry-enforced Hamiltonians and many-body methods anchored to real materials.

Materials discovery
Correlated topology
Superconductivity
Quantum devices

Featured work

Real materials, emergent phases.

Each project begins with a materials-realistic electronic structure and follows it toward correlation, superconductivity, transport, or device function.

Planar and vertically integrated transistors with polarity engineering at a molybdenum disulfide chromium oxychloride interface — From planar scaling to vertically integrated van der Waals electronics. Figure 1 from Guo et al., Nature 630, 346–352 (2024), CC BY 4.0.

01 Nature · 2024

Polarity-engineered vertical logic.

A CrOCl interface reconfigures the carrier polarity of MoS₂, enabling both n-type and p-type transistors to be integrated vertically rather than only scaled across a plane.

Electronic-structure calculations connect the interfacial surface state with the observed device behavior, linking atomically controlled materials physics to three-dimensional complementary logic.

Van der Waals interfaces
Interface DFT
3D logic

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Strain × dielectric screening

QSHHOTIMetalTrivial

interaction-driven phase space

Original concept illustration: topology changes as strain, screening, and electronic interactions are tuned.

02 Physical Review X · 2026

Interaction-driven topological transitions in TaIrTe₄.

Materials-derived tight-binding and Hartree–Fock calculations map metallic, trivial, quantum spin Hall, and higher-order topological phases near the van Hove singularities of monolayer TaIrTe₄.

Strain and dielectric screening act as experimentally accessible control parameters, while band-projected exact diagonalization and transport at fractional fillings point toward time-reversal-symmetric fractional topology.

Hartree–Fock
Exact diagonalization
Quantum spin Hall

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Electronic band structure, lattice structure, and electrical characterization of monolayer tantalum iridium telluride — Electronic structure, crystal lattice, and device characterization of monolayer TaIrTe₄. Figure 1 from Tang et al., Nature 628, 515–521 (2024). © Springer Nature.

03 Nature · 2024

A dual quantum spin Hall insulator.

Electrostatic gating moves monolayer TaIrTe₄ between a conventional quantum spin Hall gap and a second gap generated by density-tuned electronic correlations.

The two regimes share helical boundary transport but arise from different microscopic mechanisms, making one material a controllable platform for comparing single-particle and interaction-driven topology.

Correlations
Helical edges
Density tuning

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Electrostatically programmed lattice

1 × 1

⇄

superlattice

non-volatile structural memory

Original concept illustration: gating writes and erases a long-period lattice configuration in monolayer TaIrTe₄.

04 Nature · 2026

Electrically switchable superlattice memory.

Monolayer TaIrTe₄ hosts a long-period superlattice that can be written and erased non-volatilely by electrostatic tuning of its low-energy quantum spin Hall electrons.

Coupled but distinct lattice and electronic instabilities enable nanoscale structural memory and switchable correlated states at fractional superlattice fillings.

Bistability
Superlattice
Non-volatile memory

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Crystal structure, polarization-resolved second-harmonic generation, nonlinear Hall response, and Berry-curvature-dipole distribution of few-layer tantalum iridium telluride — Large room-temperature nonlinear Hall effect in few-layer TaIrTe₄. Figure 1 from Xi et al., Nature Electronics 8, 578–586 (2025). © Springer Nature.

05 Nature Electronics · 2025

A correlated topological semimetal becomes a terahertz detector.

Few-layer TaIrTe₄ combines a large room-temperature nonlinear Hall response with terahertz nonlinear electrodynamics, enabling zero-bias detection across 0.1–10 THz.

Electrostatic gating strengthens electronic correlations and sharply improves sensitivity, connecting correlated topological matter with practical broadband and ultrafast sensing.

Nonlinear Hall effect
THz detection
Correlations

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Charge-density-wave instability, reconstructed electronic bands, and enhanced Berry-curvature dipole in ultrathin tantalum iridium telluride — A 15-unit-cell charge-density wave reconstructs the bands and enhances Berry-curvature-dipole hotspots. Figure 4 from Jiang et al., Nature Communications 16, 6351 (2025), CC BY-NC-ND 4.0.

06 Nature Communications · 2025

Nonlinear Hall transport maps a correlated topological phase.

Nonlinear Hall measurements reveal a correlated charge-density-wave state in few-layer TaIrTe₄ through a dramatic enhancement of nonlinear conductivity and Berry-curvature redistribution.

Raman spectroscopy, second-harmonic generation, and first-principles theory identify a one-dimensional charge order and establish nonlinear transport as a sensitive probe of correlated topological phases.

Charge-density wave
Berry curvature
Nonlinear transport

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Vortex ↔ π junction

tractable Majorana diagnostics

Original concept illustration: deforming a vortex into intersecting π junctions preserves the relevant topology.

07 Research preprint · 2025

Intertwining Josephson and vortex topologies.

Direct simulation of a realistic superconducting vortex is computationally prohibitive. A Josephson–vortex correspondence maps the same bound-state topology onto tractable π-junction calculations.

The strategy enables first-principles searches for Majorana platforms without constructing enormous vortex supercells, and was demonstrated for conventional superconductors including 2M-WS₂ and Sr₃SnO.

Majorana modes
BdG topology
π junctions

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Fermi surfaces and nontrivial surface arcs connecting single and projected double massive Dirac bands on the beta-tungsten 001 surface — Fermi surfaces and surface states of β-W(001) at 87 meV below the Fermi level and at the Fermi level. Figure 6 from Li et al., Physical Review B 99, 165110 (2019). © 2019 American Physical Society.

08 Physical Review B · 2019

Topological massive Dirac fermions in β-tungsten.

First-principles electronic structure revealed 24 symmetry-related massive Dirac fermions generated when spin–orbit coupling gaps an underlying nodal-line structure.

The mechanism connects topology with β-W's large spin Hall response and suggests a possible microscopic origin for this experimentally important transport property.

Massive Dirac fermions
Spin Hall effect
β-W

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Topological catalysis

HHΔG_H* ≈ 0topological surface states → HER

Original concept illustration: topological catalysis connects drumhead surface states with active sites for hydrogen evolution.

09 Science China Materials · 2018

Topological catalysis for hydrogen evolution in TiSi.

TiSi’s Dirac nodal line generates drumhead-like surface states proposed as the active platform for hydrogen evolution, linking band topology directly to surface chemistry.

First-principles calculations predict near-zero hydrogen-adsorption free energies on the (010) and (110) surfaces and trace charge transfer from the topological surface state into adsorbed hydrogen.