arXiv subjects

Takashi Uchihashi

Publications and source records attributed to Takashi Uchihashi.

21 records · Page 2Linked to original sources

arXiv2008

Quantum modulation of the Kondo resonance of Co adatoms on Cu/Co/Cu(100)

Low-temperature scanning tunneling spectroscopy reveals that the Kondo temperature T_K of Co atoms adsorbed on Cu/Co/Cu(100) multilayers varies between 60 K and 134 K as the Cu film thickness decreases from 20 to 5 atomic layers. The observed change of T_K is attributed to a variation of the density of states at the Fermi level ρ_F induced by quantum well states confined to the Cu film. A model calculation based on the quantum oscillations of ρ_F at the belly and the neck of the Cu Fermi surface reproduces most of the features in the measured variation of T_K.

cond-mat.mes-hall↗

arXiv2002

Phase transition of the Si(111)-4x1-In surface reconstruction investigated by electron transport measurements

We measure the electron conductivity of the surface states and the subsurface space charge layer originating from the Si(111)-4x1-In reconstruction as a function of temperature. The conductivity of the surface states drops sharply around 130 K with decreasing temperature, revealing a metal-insulator phase transition of the surface reconstruction. In contrast, the influence of the phase transition on the conductivity of the space charge layer is limited to temperatures above 60 K. This means that the surface Fermi level remains strongly pinned despite the phase transition, indicating the presence of free carriers in the surface states down to rather low temperatures.

cond-mat.mtrl-sci↗

arXiv2002

Electron conduction through quasi-one-dimensional indium atomic wires on silicon

Electron conduction through quasi-one-dimensional (1D) indium atomic wires on silicon (the Si(111)-4x1-In reconstruction) is clarified with the help of local structural analysis using scanning tunneling microscopy. The reconstruction has a conductance per square as high as 100 uS, with global conduction despite numerous surface steps. A complete growth of indium wires up to both the surface steps and the lithographically printed electrodes is essential for the macroscopic transport. The system exhibits a metal-insulator transition at 130 K, consistent with a recent ultraviolet photoemission study [H. W. Yeom, S. Takeda, E. Rotenberg, I. Matsuda, K. Horikoshi, J. Schaefer, C. M. Lee, S. D. Kevan, T. Ohta, T. Nagao, and S. Hasegawa, Phys. Rev. Lett. 82, 4898 (1999)]

cond-mat.mtrl-sci↗