Research

With the rapid development of micro-nano processing technology centered on photolithography, the gate length of transistors in integrated circuits has gradually decreased to the same order of magnitude as the average mean free path of energy carriers (such as phonons and electrons), invalidating the macroscopic description of thermal conduction phenomena based on Fourier’s law. Meanwhile, recent advances in simulation tools (first-principles calculations, machine learning potentials, Boltzmann transport equation, molecular dynamics, etc.) have led to new insights into phonon transport and scattering mechanisms. In this context, we aim to conduct in-depth theoretical research on anharmonic phonon behavior at finite temperatures to address the challenges encountered by the traditional theoretical framework based on the lowest-order perturbation method plus linear Boltzmann transport equation in dealing with complex systems such as non-periodic lattices, inter-band quantum tunneling effects and higher-order strong anharmonicity, to better understand and manipulate the microscopic flow of energy.

Building upon prior experience, we intend to conduct a theoretical investigation in three aspects concerning the critical thermal conduction process that limits the efficient heat dissipation for the next-generation phase-change memory devices, namely, the thermal conduction conversion mechanism during crystalline-to-amorphous transition, low-dimensional heat conduction, and interface thermal resistance. The aim is to clarify the competing mechanisms among different phonon scattering processes induced by decreased spatial dimensions, structural ordering, and phonon harmonicity and to establish a computational framework bridging microscale phonon behavior and macroscopic heat conduction. Ultimately, this endeavor seeks to provide quantitative theoretical foundations for thermal transport and management in the practical application of phase-change memory devices.