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arXiv 1612.05331cond-mat.mtrl-sci
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用离子轰击和退火制备Bi $_{2}$ Se $_{3}$中的清洁表面和Se空位

Preparation of clean surfaces and Se vacancy formation in Bi$_{2}$Se$_{3}$ by ion bombardment and annealing

Weimin Zhou, Haoshan Zhu, Connie M. Valles, Jory A. Yarmoff

摘要:

硒化铋(Bi $_{2}$ Se $_{3}$)是一种拓扑绝缘体(TI),具有五层堆叠结构。单晶表面通常通过机械劈裂来制备。本工作探讨了使用低能量Ar $^{+}$离子轰击和退火(IBA)作为替代方法,以产生可重复的和稳定的Bi $_{2}$ Se $_{3}$表面在超高真空(UHV)下。结果表明,1 keV Ar $^{+}$离子轰击和30 min退火可以制备出有序的表面。低能电子衍射(LEED)和详细的低能离子散射(LEIS)的测量结果表明,IBA制备的表面和$\textit{in situ}$在超高真空中裂解制备的表面之间没有差异。对LEED图案的分析表明,最佳退火温度为450°C。角LEIS扫描揭示了当退火温度超过520°C时表面Se空位的形成。

英文摘要:

Bismuth Selenide (Bi$_{2}$Se$_{3}$) is a topological insulator (TI) with a structure consisting of stacked quintuple layers. Single crystal surfaces are commonly prepared by mechanical cleaving. This work explores the use of low energy Ar$^{+}$ ion bombardment and annealing (IBA) as an alternative method to produce reproducible and stable Bi$_{2}$Se$_{3}$ surfaces under ultra-high vacuum (UHV). It is found that a well-ordered surface can be prepared by a single cycle of 1 keV Ar$^{+}$ ion bombardment and 30 min of annealing. Low energy electron diffraction (LEED) and detailed low energy ion scattering (LEIS) measurements show no differences between IBA-prepared surfaces and those prepared by $\textit{in situ}$ cleaving in UHV. Analysis of the LEED patterns shows that the optimal annealing temperature is 450°C. Angular LEIS scans reveal the formation of surface Se vacancies when the annealing temperature exceeds 520°C.

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