High-Pressure Phase Transitions and Structures of Topological Insulator BiTeI

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• 作者：Yuanzheng Chen ; Xiaoxiang Xi ; Wai-Leung Yim ; Feng Peng ; Yanchao Wang ; Hui Wang ; Yanming Ma ; Guangtao Liu ; Chenglin Sun ; Chunli Ma ; Zhiqiang Chen ; H. Berger
• 刊名：Journal of Physical Chemistry C
• 出版年：2013
• 出版时间：December 5, 2013
• 年：2013
• 卷：117
• 期：48
• 页码：25677-25683
• 全文大小：582K
• 年卷期：v.117,no.48(December 5, 2013)
• ISSN：1932-7455

文摘

Being a giant bulk Rashba semiconductor, the ambient-pressure phase of BiTeI was predicted to transform into a topological insulator under pressure at 1.7鈥?.1 GPa [ Nat. Commun. 2012, 3, 679]. Because the structure governs the new quantum state of matter, it is essential to establish the high-pressure phase transitions and structures of BiTeI for better understanding its topological nature. Here, we report a joint theoretical and experimental study up to 30 GPa to uncover two orthorhombic high-pressure phases of Pnma and P4/nmm structures named phases II and III, respectively. Phases II (stable at 8.8鈥?8.9 GPa) and III (stable at >18.9 GPa) were first predicted by our first-principles structure prediction calculations based on the calypso method and subsequently confirmed by our high-pressure powder X-ray diffraction experiment. Phase II can be regarded as a partially ionic structure, consisting of positively charged (BiTe)⁺ ladders and negatively charged I^{鈥?/sup> ions. Phase III is a typical ionic structure characterized by interconnected cubic building blocks of Te鈥揃i鈥揑 stacking. Application of pressures up to 30 GPa tuned effectively the electronic properties of BiTeI from a topological insulator to a normal semiconductor and eventually a metal having a potential of superconductivity.}