Research

Our focus lies in the study of electronic transport in two-dimensional quantum materials, investigating their structures and heterostructures to uncover novel electronic phenomena, with the aim to elucidate the underlying physical mechanisms. This endeavor heavily relies on research into transport within nanodevices, which we design and assemble to probe targeted electronic processes. Furthermore, we employ a broad range of control methods, including high pressure, stress, and ionic liquid gating, to explore and manipulate the properties of 2D materials.

Topological Materials

We primarily focus on the quantum effects observed in MnBi₂Te₄ (MBT) family materials, which are intrinsic magnetic topological insulators characterized by nontrivial band topology, two dimensionality, and intrinsic magnetism. We have detected the quantum anomalous Hall effect in devices with an odd number of layers of MBT (Nature 340, 167 (2025)) and the axion insulator state in devices with even layers (Nat. Mater. 19, 522 (2020)). Furthermore, we have discovered a giant nonlocal resistance exclusively in the axion insulator state of even-layer samples (Sci. Bull., 68, 12, 1252 (2023)) and observed a zero Hall plateau under a pulsed magnetic field (Nat. Commun. 12, 4647 (2021)). Additionally, we identify that gate-voltage oscillations result in significant nonlinear transport signals in MBT, and we propose a methodology to mitigate this effect by grounding the voltage electrodes during second harmonic measurements. The interaction of various quantum order parameters in the layered antiferromagnetic MBT has opened up new avenues for the exploration of topological quantum phases of matter.

Ionic Gating of Electronic Devices

In this research direction, we achieve electric-field-controlled reversible hydrogenation in graphene using hydrogen ion electrolytes, enabling the fabrication of monolayer graphene FETs with on/off ratios reaching 108 at room temperature and exhibiting high stability for up to 1 million cycles (Nat. Electron. 4, 254 (2021)). The switching speed is governed by Tafel kinetics of hydrogenation reactions in the two-dimensional limit, with the response time capable of reaching the order of tens of microseconds (ACS Appl. Mater. Interfaces, 14, 47991 (2022)). Furthermore, we demonstrate gate-tunable neuromorphic functionality transitions between artificial neurons and synapses within monolayer graphene transistors, enabling their operation as memtransistors or synaptic transistors as needed (Nano Lett., 24, 5, 1620 (2024)). Additionally, layer-by-layer DEME⁺ ion intercalation enables multistate modulation in few-layer graphene systems (Sci. China-Phys. Mech. Astron. 68, 247413 (2025)).

2D Oxide Heterointerface

The KTaO₃ based heterointerface is our currently ongoing research project, which presents a compelling interplay between two-dimensional superconductivity and ferromagnetism. This coexistence is pivotal for understanding the mechanisms behind unconventional superconductivity. At the CaZrO₃/KTaO₃ (111) interface, we have observed fascinating hysteretic magnetoresistance loops within the superconducting state. Notably, a butterfly-shaped hysteresis manifests alongside the superconducting zero resistance, with the peak amplitude increasing in correlation with the magnetic field sweep rate. This behavior highlights the dynamics of magnetization in the superconducting phase. These insights provide an innovative platform for exploring the interaction between magnetism and superconductivity, enabling the development of phase-sensitive devices at KTaO₃-based oxide heterointerfaces（Nat Commun., 16,1, 3035 (2025)）.

Rhombohedral Graphene

In this ongoing research direction, we aim to investigate quantum effects in rhombohedral graphene/hBN moiré superlattices. By tuning the twist angle and spin-orbit proximity, we can engineer the flat bands and explore a range of emergent quantum phenomena, including superconductivity, magnetism, correlated insulating state, Chern insulator state, and Wigner crystal. Here we pay close attention to the observation of robust integer/fractional quantum anomalous Hall effects by optimizing the heterostructure quality, twist precision, and proximity interactions. This study seeks to elucidate the interplay between correlation effects and topology in these two-dimensional materials, providing insights into their potential applications in quantum electronics and topological quantum computation.