Research

Overview

As digital transformation (DX) and AI continue to spread rapidly, the energy consumption of data centers is rising year by year. Addressing this trend requires the efficient use of renewable energy and the establishment of advanced technologies for waste-heat recovery. In cutting-edge areas such as quantum technologies, temperature management critically affects device performance and operational stability, making precise control indispensable. A deep understanding of energy-transport phenomena—particularly thermal transport—and the ability to control them are increasingly demanded across industries as a foundation for a sustainable society.

To meet these societal needs, our laboratory aims to understand materials properties from a microscopic perspective and to build the scientific principles and technologies for controlling them. Through an integrated approach that combines theory, numerical simulation, and measurement techniques, we elucidate materials properties across multiple length scales—from the nanoscale to the bulk—and pursue the creation of novel functional materials and devices.

Projects

Interfacial thermal engineering

As devices continue to shrink, thermal boundary resistance (TBR) becomes comparable to—or even dominates over—the bulk thermal resistance. Controlling TBR is therefore crucial for effective thermal management in semiconductors and advanced packaging. The TBR between dissimilar materials depends on a complex set of factors, including atomic bonding configuration, interfacial roughness, contamination, lattice mismatch, defects, and residual stress.

In this project, we combine atomistic simulations—molecular dynamics (MD) and non-equilibrium Green’s functions (NEGF)—with precision thermal metrology based on time-domain and frequency-domain thermoreflectance (TDTR/FDTR) to elucidate the mechanisms of interfacial heat transport. Building on these insights, we actively engineer TBR through interface modification, insertion of interlayers, and optimization of joining conditions, aiming to establish design rules that let us transmit or block heat on demand.

Multiscale Characterization of Hierarchical Nanostructures

Low-dimensional materials such as carbon nanotubes and graphene exhibit outstanding mechanical, electrical, and thermal properties; however, their intrinsic performance often degrades substantially during bulk processing (e.g., film formation or fiber spinning). In bulk form, assemblies of these nanoscale building blocks interact to create multi-scale, networked architectures of high complexity.

In this project, we employ coarse-grained molecular dynamics (CGMD) and related molecular simulation techniques to reproduce the complex formation processes of real materials, and integrate them with network-science approaches to identify the structural determinants of transport properties—in particular, heat and charge conduction.

Spatiotemporal thermal control

We aim to actively manipulate phonons—the quanta of lattice vibrations—in both time and space to achieve dynamic, directional control of heat conduction. Focusing on low-dimensional materials, we apply external stimuli—electric and magnetic fields, optical excitation, and electrochemical doping—to enable instantaneous switching of thermal conductivity. We further pursue spatiotemporal modulation of conductivity to introduce nonreciprocity in heat transport and realize thermal-diode functionality.