[21p-C106-1~11] 6.5 Surface Physics, Vacuum

▲ [21p-C106-1] [INVITED] Identifying an anomalous phonon mode in SiGe alloy using Molecular Dynamics Simulation

〇Sylvia Yuk Yee Chung¹, Motohiro Tomita^1,2, Junya Takizawa¹, Ryo Yokogawa^3,4, Atsushi Ogura^3,4, Haidong Wang⁵, Takanobu Watanabe^1,2 (1.Waseda Univ., 2.Comprehensive Research Org., Waseda Univ., 3.Meiji Univ., 4.Meiji Renewable Lab., 5.Key Lab. Thermal Sci. Power Eng. Tsinghua Univ.)

Keywords:phonons, SiGe alloy, atomistic

One of the phonon modes produced by bulk SiGe alloy occurs within the range of 3-4 THz, is speculated to be localized, and has yet to be identified. In order to unravel some insight into the origins of this particular phonon mode, bulk SiGe alloys of varying Si, Ge spatial distributions were simulated using Molecular Dynamics. Investigating different Brillouin zones revealed the optical nature of this local mode, cluster sizes were simulated to elucidate the local mode composition, and atomic mass differences revealed the dependence on both Si and Ge. An atomistic model of the local mode is proposed, which depicts this phonon to be comprised of small Ge clusters surrounded by Si atoms, and is a collective vibration of these components, but also including movement from the Si-Ge atoms at the cluster periphery.