EVIDENCE OF A BIPOLARONIC, INSULATING STATE OF NA SUBMONOLAYER ON GAAS(110)

被引:16
作者
DELPENNINO, U [1 ]
SALVARANI, B [1 ]
COMPANO, R [1 ]
PANKRATOV, O [1 ]
机构
[1] LAWRENCE LIVERMORE NATL LAB,LIVERMORE,CA 94551
来源
PHYSICAL REVIEW B | 1995年 / 52卷 / 15期
关键词
D O I
10.1103/PhysRevB.52.10717
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
We present electron-energy-loss-spectroscopy results for the Na/GaAs(110) ultrathin interface. The data do not show the loss features commonly found for Cs, K, and Rb overlayers, which are considered to be the fingerprints of a Mott-Hubbard insulating state of the interface. In photoemission we observe a distinct Na-induced surface state, appearing at a coverage of about 0.25 ML, which disappears approaching the complete monolayer. We interpret our results on the basis of the bipolaron model which suggests that insulating character of the interface originates from the ''negative-U'' behavior of the surface state.
引用
收藏
页码:10717 / 10720
页数:4
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