Spectroscopic evidence of a topological quantum phase transition in ultrathin Bi2Se3 films

被引：120

作者：

Sakamoto, Yusuke ^{[1
]}

Hirahara, Toru ^{[1
]}

Miyazaki, Hidetoshi ^{[2
]}

Kimura, Shin-ichi ^{[2
]}

Hasegawa, Shuji ^{[1
]}

机构：

[1] Univ Tokyo, Dept Phys, Bunkyo Ku, Tokyo 1130033, Japan

[2] Inst Mol Sci, UVSOR Facil, Okazaki, Aichi 4448585, Japan

来源：

PHYSICAL REVIEW B | 2010年 / 81卷 / 16期

关键词：

SINGLE DIRAC CONE; SPIN HALL; INSULATOR; SURFACE; STATE; TRANSPORT; WELLS;

D O I：

10.1103/PhysRevB.81.165432

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

We have measured the band dispersion of ultrathin Bi2Se3 films formed on a silicon substrate using angle-resolved photoemission spectroscopy. An energy gap opening in the topological surface-state bands of the three-dimensional topological insulator Bi2Se3 is observed due to the hybridization of the top and bottom surfaces. The drastic change in the shape of the band structure and the reversal of the size of the energy gap between 2 and 3 quintuple layer (QL) films indicate that the parity of the conduction and valence bands are exchanged by finite-size effects. The analyses based on an effective four-band model also support the occurrence of a quantum topological phase transition, thus, implying that 2 QL films are trivial while the 3 QL films are in the quantum spin Hall state.

引用

页数：4

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