Surface-State Bipolaron Formation on a Triangular Lattice in the sp-Type Alkali-Metal/Si(111) Mott Insulator

被引：19

作者：

Cardenas, L. ^{[1
]}

Fagot-Revurat, Y. ^{[1
]}

Moreau, L. ^{[1
]}

Kierren, B. ^{[1
]}

Malterre, D. ^{[1
]}

机构：

[1] Nancy Univ, CNRS, Inst Jean Lamour, UMR 7198, F-54506 Vandoeuvre Les Nancy, France

来源：

PHYSICAL REVIEW LETTERS | 2009年 / 103卷 / 04期

关键词：

TRANSITION; INTERFACES; BEHAVIOR;

D O I：

10.1103/PhysRevLett.103.046804

中图分类号：

O4 [物理学];

学科分类号：

0702 ;

摘要：

We report on new low-energy electron diffraction, scanning tunneling microscopy, and angle-resolved photoemission spectroscopy studies of alkali-metal/Si(111) previously established as having a Mott-insulating ground state at surface. The observation of a strong temperature dependent Franck-Condon broadening of the surface band together with the novel root 3 X root 3 -> 2(root 3 X root 3) charge and lattice ordering below 270 K evidence a surface charge density wave in the strong electron-phonon coupling limit (g approximate to 8). Both the adiabatic ratio (h) over bar omega(0)/t approximate to 0.8 and the effective pairing energy V-eff = U - 2g (h) over bar omega(0) approximate to -800 meV are consistent with the possible formation of a bipolaronic insulating phase consisting of alternating doubly occupied and unoccupied dangling bonds as expected in the Holstein-Hubbard model.

引用

页数：4

共 34 条

[1] Electron-phonon interaction at the Si(111)-7x7 surface [J].