발표연사 ▶▶▶

부문 Track
성명 Noejung Park, Professor
소속 Department of Physics, Ulsan National Institute of Science and Technology, Ulsan, 689-798 Korea
주제 Ab Initio study of band topologies and spin-phonon dynamics through real-time equations of motion
학력 1994. 서울대학교 공과대학 졸업(공학사)
1997. 서울대학교 자연과학대학 물리학과(이학석사)
2002. 서울대학교 자연과학대학 물리학과(이학박사)
경력 2005.~2011. 단국대학교 응용물리학과 조교수
2011.~2013. 울산과기대 부교수
2013.~현재. 울산과학기술원 교수
요약 Topological phases of solid state bands have been widely examined in these days condensed matter field, and global properties immune to local perturbations have
been explored as topologically non-trivial observables.
The computations of topological quantities of real materials are affordable only through the theories of linear responses over the static ground electronic structure.
Here, we propose a conceptually novel and general method: we perform the time evolution of the solid state, , through the time-dependent Schrödinger equation, and calculate physical observables such as charge current or spin current as an expectation value that can be obtained from the time-evolving states.
We present exemplary cases of trivial insulator, a spin-frozen valley-Hall system, a spin-frozen Haldane-Chern insulator, and quantum spin-Hall insulators.
The same real-time dynamics is also used for the phonon-coupled spin dynamics of semiconductors with strong spin-orbit coupling. We present that the spin precession dynamics of MoS2 in which the spin is strongly coupled to the optical phonon.
This dynamical spin state can be resolved into discrete Floquet-phononic spectra, and once the phonon is pumped so as to break time-reversal symmetry, the resulting spin-Floquet structures induce net out-of-plane magnetizations in the otherwise non-magnetic 2D material.