Topological metal at the surface of an ultrathin Bi1-xSbx alloy film

被引:53
作者
Hirahara, T. [1 ]
Sakamoto, Y. [1 ]
Saisyu, Y. [1 ]
Miyazaki, H. [2 ]
Kimura, S. [2 ]
Okuda, T. [3 ]
Matsuda, I. [3 ]
Murakami, S. [4 ]
Hasegawa, S. [1 ]
机构
[1] Univ Tokyo, Dept Phys, Bunkyo Ku, Tokyo 1130033, Japan
[2] Natl Inst Nat Sci, Inst Mol Sci, UVSOR Facil, Okazaki, Aichi 4448585, Japan
[3] Univ Tokyo, ISSP, Synchrotron Radiat Lab, Kashiwa, Chiba 2778581, Japan
[4] Tokyo Inst Technol, Dept Phys, Tokyo 1528551, Japan
来源
PHYSICAL REVIEW B | 2010年 / 81卷 / 16期
关键词
INSULATOR;
D O I
10.1103/PhysRevB.81.165422
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
We have studied the growth and electronic/transport properties of ultrathin Bi1-xSbx alloy films, which the bulk is reported to be a topological insulator for 0.07 < x < 0.22. We found that single crystal epitaxial films as thin as similar to 30 angstrom could be grown on silicon for 0 <= x < 0.32. The Z(2) topological number of the films was shown to be nontrivial from the surface Fermi surface. Moreover a crossover from an insulating to a metallic behavior was observed upon reducing the film thickness, revealing the clear detection of the topological-metal conductivity. Our results settle the controversial issues concerning the metallicity of Bi1-xSbx at low temperature and verify that the surface/volume ratio must be extensively enhanced to properly understand the nature of these surface states.
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页数:5
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