Phase change material

Phase-change materials

Phase-change materials (PCMs) have been widely studied for information storage, electronic devices, and thermal/chemical sensors etc. In many PCMs, electrons strongly interact with each other and the electronic structure is very sensitive to the external perturbation. We are working on the (thermal-, photo-, pressure-induced) phase transition mechanism of Vanadium dioxide (VO2). We have shown that defects are critical to trigger the phase transition. Very recently we highlighted the important role of a particular phonon at 6THz in the structural phase transition. Based on that, a strong interplay between the electron and lattice freedom has been proposed in the phase transition, which should be quite general in all the strongly correlated materials.

We show that by manipulating the interface of a Au/VO2 hybrid material, ultrafast photo-induced phase transition can be achieved. At present, we are also carrying out research on VO2-based nano sensors for small molecules.  The work was done in close collaboration with Prof. Richard F. Haglund (Physics, Vanderbilt).

See Nano Lett. 14, 1127 (2014); Nano Lett. 13, 798 (2013); Nano Lett. 12, 780 (2012); APL 104, 101913 (2014)