Disproportionation phenomena on free and strained Sn/Ge(111) and Sn/Si(111) surfaces

被引：37

作者：

Ballabio, G

Profeta, G

de Gironcoli, S

Scandolo, S

Santoro, GE

Tosatti, E

机构：

[1] SISSA, I-34014 Trieste, Italy

[2] Ist Nazl Fis Mat, DEMOCRITOS, I-34014 Trieste, Italy

[3] Ist Nazl Fis Mat, Unita Aquila, I-67010 Coppito, LAquila, Italy

[4] Princeton Univ, Princeton Mat Inst, Princeton, NJ 08540 USA

[5] Int Ctr Theoret Phys, I-34014 Trieste, Italy

[6] Univ Aquila, Dept Phys, I-67010 Coppito, LAquila, Italy

来源：

PHYSICAL REVIEW LETTERS | 2002年 / 89卷 / 12期

关键词：

D O I：

10.1103/PhysRevLett.89.126803

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

Distortions of the root3 x root3- Sn/Ge(111) and Sn/Si(111) surfaces are shown to reflect a disproportionation of an integer pseudocharge, Q, related to the surface band occupancy. A novel understanding of the (3 x 3)-1U ("1 up, 2 down") and 2U ("2 up, 1 down") distortions of Sn/Ge(111) is obtained by a theoretical study of the phase diagram under strain. Positive strain keeps the unstrained value Q = 3 but removes distortions. Negative strain attracts pseudocharge from the valence band causing first a (3 X 3)-2U distortion (Q = 4) on both Sn/Ge and Sn/Si, and eventually a (root3 x root3)-3U ("all up") state with Q = 6. The possibility of a fluctuating phase in unstrained Sn/Si(111) is discussed.

引用

页码：126803 / 126803

页数：4

共 32 条

[1] SiC(0001): A surface Mott-Hubbard insulator [J].