My research focuses on computational condensed matter physics (mostly solid and interface) in structural and thermodynamic behavior of complex and disordered systems. Primary interest is the application and development of classical/quantum and statistical mechanical methodologies to gain insight into the fundamental characteristics of crystal solids, clusters, quantum fluid and how they influence the physical properties of the material (mainly studying structural properties, phase transitions and excitation energies). Typical approaches in current or recent use include ab initio calculations based on density functional theory, cluster variation/expansion method, series expansion method, and a variety of simulation approaches, such as classical Monte Carlo/Molecular Dynamics (MD), and ab initio MD, Quantum Monte Carlo, as well as global optimization algorithms for the exploration of multi-dimensional energy surfaces. The main directions which are undertaking or considering are as follows:

• (1)Compressibility and Hugoniot properties of pure metals, alloys and porous materials; structural and electronic properties of alloys, semiconductors, mineral crystals and other Lattice model related systems, especially the equation of state (EOS), phase stability, phase diagrams, site preference, and lattice vibration entropy, based on first-principles calculations. The methods used for this purpose are inverse methods (Chen's Lattice Inversion for Potentials and Cluster Expansion Method) and statistical methods (Cluster Variation Method, series expansion, and Renormalization Group Method).
  Current task is to generalize conventional Ising model to take account of local distortions of lattice (parallel with continuous displacement formulation of CVM) and to combine pair potential with conventional CEM scheme to obtain accurate effective cluster interactions for modelling order-disorder transitions, solid-liquid and liquid-gas transformations more realistically. Besides, order-disorder process has considerable effects on equation of state and thermal expansion coefficient of alloys and compounds. It is believed same conclusion holds for semiconductors and mineral crystals. This kind of behavior has not been reported before and it is worthwhile to investigate its impacts on alloys theory and geophysics.
• (2) Electronic and thermodynamic properties of UO2 and CeO2, which has a band gap about 2 eV and exhibits some semiconductor characteristics. Employing LSDA+U method, we investigated the influences of localization of f electrons on band structure and energy gap variations along external pressures. Also, with classical MD simulations to reveal the mystery of unusual self-healing ability of UO2 under irradiation damages.