Revelation of Topological Surface States in Bi2Se3 Thin Films by In Situ Al Passivation

详细信息    查看全文

• 作者：Murong Lang ; Liang He ; Faxian Xiu ; Xinxin Yu ; Jianshi Tang ; Yong Wang ; Xufeng Kou ; Wanjun Jiang ; Alexei V. Fedorov ; Kang L. Wang
• 刊名：ACS Nano
• 出版年：2012
• 出版时间：January 24, 2012
• 年：2012
• 卷：6
• 期：1
• 页码：295-302
• 全文大小：994K
• 年卷期：v.6,no.1(January 24, 2012)
• ISSN：1936-086X

文摘

Topological insulators (TIs) are extraordinary materials that possess massless, Dirac-like topological surface states in which backscattering is prohibited due to the strong spin鈥搊rbit coupling. However, there have been reports on degradation of topological surface states in ambient conditions, which presents a great challenge for probing the original topological surface states after TI materials are prepared. Here, we show that in situ Al passivation inside a molecular beam epitaxy (MBE) chamber could inhibit the degradation process and reveal the pristine topological surface states. Dual evidence from Shubnikov鈥揹e Hass (SdH) oscillations and weak antilocalization (WAL) effect, originated from the 蟺 Berry phase, suggests that the helically spin-polarized surface states are well preserved by the proposed in situ Al passivation. In contrast, we show the degradation of surface states for the unpassivated control samples, in which the 2D carrier density is increased 39.2% due to ambient n-doping, the SdH oscillations are completely absent, and a large deviation from WAL is observed.

Keywords:

topological insulator; aluminum passivation; thin films; Shubnikov鈭抎e Hass oscillations; weak antilocalization; surface state degradation