Magnetic Doping and Kondo Effect in Bi2Se3 Nanoribbons

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• 作者：Judy J. Cha ; James R. Williams ; Desheng Kong ; Stefan Meister ; Hailin Peng ; Andrew J. Bestwick ; Patrick Gallagher ; David Goldhaber-Gordon ; Yi Cui
• 刊名：Nano Letters
• 出版年：2010
• 出版时间：March 10, 2010
• 年：2010
• 卷：10
• 期：3
• 页码：1076-1081
• 全文大小：384K
• 年卷期：v.10,no.3(March 10, 2010)
• ISSN：1530-6992

文摘

A simple surface band structure and a large bulk band gap have allowed Bi₂Se₃ to become a reference material for the newly discovered three-dimensional topological insulators, which exhibit topologically protected conducting surface states that reside inside the bulk band gap. Studying topological insulators such as Bi₂Se₃ in nanostructures is advantageous because of the high surface-to-volume ratio, which enhances effects from the surface states; recently reported Aharonov−Bohm oscillation in topological insulator nanoribbons by some of us is a good example. Theoretically, introducing magnetic impurities in topological insulators is predicted to open a small gap in the surface states by breaking time-reversal symmetry. Here, we present synthesis of magnetically doped Bi₂Se₃ nanoribbons by vapor−liquid−solid growth using magnetic metal thin films as catalysts. Although the doping concentration is less than 2%, low-temperature transport measurements of the Fe-doped Bi₂Se₃ nanoribbon devices show a clear Kondo effect at temperatures below 30 K, confirming the presence of magnetic impurities in the Bi₂Se₃ nanoribbons. The capability to dope topological insulator nanostructures magnetically opens up exciting opportunities for spintronics.