Research Interests

With burgeoning interest in quantum technology, I recently focus on possible ways of utilizing graphene as a candidate for quantum computing, via strain engineering of graphene. Elastic strain in graphene generates pseudo-magnetic fields, and Dirac fermions can be strongly localized or guided by designed strain patterns.

My ongoing research is highly concentrated on creation of controllable qubits in graphene via strain engineering. A nanobubble formed in graphene sheets can host a strong localization of Dirac fermions, and results in quantum dots. Strain-induced single/double quantum dots can be implemented for creating spin/charge qubits, and quantum states of the qubits are controllable by means of gate voltages and strain engineering. Initialization, modulation, and operation are all electrically enabled, so that graphene nanobubble qubits are applicable a purely electrical quantum computing.

Meanwhile, strain effects are considerable for quantum information based on graphene quantum interferometry. Since the pseudo-magnetic fields mimics 'real' magnetic fields, changes in phases acquired by Dirac fermions through a quantum inferferometry.  Based on the graphene Mach-Zehner interferometer formed at a pn junction, it is able to detect a very small phase change due to the strain. In this line, a ultrasensitive mechanical sensor is one of major topics in graphene straintronics research.

Principal interest is focused on ballistic transport in graphene with various modulations such as magnetic fields, AC driven potential, strain, structural defects, magnetic impurities etc. Graphene nanoribbons and bilayer graphene are also of interest to me.

Particularly, I have a great interest in investigating coherent transport along edge/interface of graphene in quamtum Hall regime. Thanks to its superb transport properties and stability, graphene is an almost perfect playground for understanding quantum mechanical phenomena.

Another interest is influence of mechanical or structural deformation on transport in graphene. Research topics associated with strain in graphene cover both practical and fundamental aspects: i) detection of strain-induced disorders for achieving a ballistic transport region, ii) understanding peculiar transport phenomena upon effects of strain on valley degree of freedom. Even such strain is controllable via various ways, so study of strain effects in graphene has great potential.

I am also very interested in graphene-based vertical heterostructures with 2D transition metal dichalcogenides (2DTMDs) for nanoelectronic devices. Beyond its limited application using traditional lateral architectures, vertically stacked heterostructures give us an alternative, promising, and feasible devices based on graphene, such as field-effect transistors (FETs), photo detectors, etc.

For graphene-2DTMD tunneling FETs, it has been intensively discovered that large on/off ratio of tunneling current allows for high-performance nanoelectronic devices, exploiting extraordinary transport properties of graphene. In addition, adding functionalities to the existing graphene tunneling FET is highly required for future nanoelectronics. For example, manipulation of spins and valleys of graphene, achieving high efficiency of thermal transport, broad-band and ultrafast detection of photon, accurate sensing of adhered electrochemical molecules, and so on. All aspects of possible applications fall into my research interest, designing various graphene-based device models.

Collaborations with experimentalists are welcoming, including analysis measured data and confirmation of developed device models.

Graphene has been widely accepted as a competitive candidate for photonic devices, owing to its exotic properties in terms of optical usages.  Optical response of graphene to a very wide frequency range from THz to visible is found to be attractive to recent interest from researchers. Especially, plasmonic phenomena in graphene is fairly significant due to its THz frequency range. With the controllable doping level of graphene, tunable plasmonic devices are feasible using graphene.

Also, one of secondary interests is metamaterials upon FDTD simulations on dielectric or metallic photonic crystals.