2017年第78回応用物理学会秋季学術講演会

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一般セッション(ポスター講演)

9 応用物性 » 9.5 新機能材料・新物性

[6p-PB3-1~6] 9.5 新機能材料・新物性

2017年9月6日(水) 13:30 〜 15:30 PB3 (国際センター2F)

13:30 〜 15:30

[6p-PB3-5] Ultrafast Dynamic Study of MBE Growth Bi-Topological Insulator

〇(B)Jin-Wei Li1、Tsun-I Chen1、Hsuan-Yin Chen1、Che-Wei Huang1、J.C.A. Huang2、Chao-Kuei Lee1,3 (1.Dep. of Photonics for National Sun Yat-sen University, Kaohsiung 804, Taiwan、2.Dep. of Physics for National Cheng Kung University、3.Dep. of Physics, National Sun Yat-sen University, Kaohsiung 80411, Taiwan)

キーワード:Topological Insulator, Ultrafast Dynamic Study

Topological insulators have been attracted lots of attentions due to their potential in spintronics which is attributed to special surface state from strong spin orbital interaction. To date, plenty of researches about topological insulators have been reported. However, most investigations focus on physical properties of single crystals. As a result, studies in detail to topological insulator thin film, such as grown by molecular beam epitaxy (MBE), are very important problems and in an urgent need.
In this work, we investigate the coherent phonon properties within the Bi2Se3 and Bi2Te3 films. Using Optical Pump Optical Probe Transmitted spectroscopy (OPOPT), the oscillation phenomenon was observed within the pump probe profile. This can be attribute to coherent phonon which has been discussed theoretically and predicted that the coherent phonon will be un-exist for topological insulator with thickness less than 20nm for Bi2Te3 [1] and 40nm for Bi2Se3 [2], respectively.
To confirm the conclusion from typical reflective pump probe measurement, a new type of reflective pump probe which the pump and probe beam excite the film on the opposite side was buildup. The result indicated the nature of phonon propagation. Furthermore, thickness dependent of phonon life time and relaxation time are also discussed.