Anisotropic conductivity of the Si(111)4 x 1-ln surface: Transport mechanism determined by the temperature dependence

The temperature dependence of anisotropic conductivity of a quasi-one-dimensional metallic surface, Si(111)4 x 1-ln, was measured by a variable-temperature four-tip scanning tunneling microscope. Using the square four-point probe method, we succeeded in measuring the conductivity parallel and perpen...

Full description

Saved in:
Bibliographic Details
Published in:Physical review. B, Condensed matter and materials physics Condensed matter and materials physics, 2012-07, Vol.86 (3)
Main Authors: Uetake, Tomoya, Hirahara, Toru, Ueda, Yoichi, Nagamura, Naoka, Hobara, Rei, Hasegawa, Shuji
Format: Article
Language:English
Subjects:
Anisotropy
Condensed matter
Energy gap
Metal-insulator transition
Microscopes
Scanning
Temperature dependence
Transport
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:The temperature dependence of anisotropic conductivity of a quasi-one-dimensional metallic surface, Si(111)4 x 1-ln, was measured by a variable-temperature four-tip scanning tunneling microscope. Using the square four-point probe method, we succeeded in measuring the conductivity parallel and perpendicular to the In chains independently as a function of temperature. It was shown that the conductivity perpendicular to the In chains was mainly the conductivity of the space-charge layer of the substrate. Moreover, it was clarified that it strongly depends on the substrate flashing temperature and this sometimes hindered the anisotropic conductivity at low temperatures. In contrast, the conductivity parallel to In chains was clearly dominated by the surface states and decreased drastically around 110 K by the well-known 4 x 1 to 8 x 2 metal-insulator transition. The low temperature 8 x 2 phase had an energy gap as large as ~250 meV, consistent with previous photoemission reports.
ISSN:1098-0121
1550-235X