Research

We conduct research in the field of quantum matter theory. Our research aims to deepen our understanding of quantum matter and quantum phenomena in various nanoscale systems, including topological phases of matter, strongly correlated matter, and spin-related phenomena. By exploring physical realizations such as quantum dots, nanotubes, nanowires, topological insulators, and superconductors, we seek to uncover the fundamental principles governing their behavior. In addition, we investigate strongly correlated electron systems such as high-temperature superconductors (cuprates) and heavy-fermion materials, focusing on their topological properties and the potential applications of these systems. Our goal is to advance the field of quantum matter theory and contribute to the development of new technologies in nanoelectronics and other related fields.

Two-dimensional materials

We explore the properties of two-dimensional materials, including graphene, transition metal dichalcogenides (TMDs), and boron nitride, which possess unique electronic properties distinct from their bulk counterparts. These materials have potential applications in various fields, particularly in electronics. In recent years, there has been a growing interest in twisted multilayer structures, which can exhibit strongly correlated systems and topological phases of matter. The study of these materials and their unique properties has the potential to revolutionize fields such as materials science, nanotechnology, and electronics. Our work contributes to a better understanding of correlated states in moiré structures and provides a potential avenue for the development of topological electronic devices.

Selected publications

Electrically tunable correlated domain wall network in twisted bilayer graphene, 2D Mater. 11, 035007 (2024).  

General scatterings and electronic states in the quantum-wire network of moiré systems, Phys. Rev. B 108, L121409 (2023). 

Helical liquids in nanoscale systems

We investigate helical liquids in nanoscale systems. The physical realizations include interacting electrons in one-dimensional channels appearing at the boundaries of topological materials, including edge channels of a two-dimensional topological insulator (2DTI) and hinges of a higher-order topological insulator (HOTI). We investigate the properties of the helical liquids, including their transport and spectroscopic features, as well as the realizations of topological zero modes utilizing these helical liquids, including (Kramers pairs of) Majorana zero modes in nanoscale hybrid systems consisting of 2DTI or HOTI boundary channels in proximity to an s-wave superconductor. Our work lays the foundation for further research on the interplay between topological properties and superconductivity in nanoscale systems, with potential applications in quantum computing and low-power electronics.

Selected publications

Interaction- and phonon-induced topological phase transitions in double helical liquids, Nanoscale Horiz. 9, 1725 (2024). 

Helical Liquids in Semiconductors, review article in Semicond. Sci. Technol. 36, 123003 (2021). 

Majorana Kramers Pairs in Higher-Order Topological Insulators, Phys. Rev. Lett. 121, 196801 (2018). 


Topological phases of matter

We investigate topological phases of matter in condensed matter systems, including quantum spin Hall insulators, higher-order topological insulators (HOTI), and topological superconductors. In addition, we propose several schemes to stabilize Majorana zero modes in setups based on carbon nanotubes or hinge channels of HOTI. Our work opens up opportunities for future developments in the realization and manipulation of topological phases, as well as the exploration of new materials and structures for the stabilization of Majorana zero modes and topological quantum computation.

Selected publications

Majorana Kramers Pairs in Higher-Order Topological Insulators, Phys. Rev. Lett. 121, 196801 (2018). 

Antiferromagnetic nuclear spin helix and topological superconductivity in 13C nanotubes, Phys. Rev. B 92, 235435 (2015). 

Charge-2e  skyrmion condensate in a hidden-order state, Phys. Rev. B 87, 085114 (2013). 

Topological density wave states of nonzero angular momentum, Phys. Rev. B 84, 155111 (2011). 

Charge transport in nanoscale channels

We investigate the charge transport properties of various (quasi-)one-dimensional nanoscale channels, including spin-orbit-coupled nanowires and boundary channels of topological materials. We explore the interplay between electronic correlation and spin-related phenomena, with the aim of understanding and manipulating the transport properties of these systems. Our findings provide insights into the underlying physics of these nanoscale channels and pave the way for developing new strategies to control and optimize their transport properties. The potential applications of such nanoelectronics are vast, ranging from quantum computing to high-performance sensing technologies.

Selected publications

Helical Liquids in Semiconductors, review article in Semicond. Sci. Technol. 36, 123003 (2021). 

Charge transport of a spin-orbit-coupled Luttinger liquid,  Phys. Rev. B 100, 195423 (2019). 

Effects of nuclear spins on the transport properties of the edge of two-dimensional topological insulators, Phys. Rev. B 97, 125432 (2018). 

Nuclear-spin-induced localization of the edge states in two-dimensional topological insulators, Phys. Rev. B 96, 081405(R) (2017).