Interplay of electron correlations and localization in disordered β -tantalum films: Evidence from dc transport and spectroscopic ellipsometry study

We report the dc transport (5 K ≲ T ≲ 380 K) and spectroscopic ellipsometry (0.8 eV ≤ hν ≤ 8.5 eV, T ≃ 300 K) study of β-Ta films prepared by rf sputtering deposition as a function of their thickness in the range 2.5 nm ≲ d ≲ 200 nm. The dc transport of the β-Ta films with a thickness d ≳ 25 nm is c...

Full description

Saved in:
Bibliographic Details
Published in:Applied physics letters 2015-02, Vol.106 (5)
Main Authors: Kovaleva, N. N., Chvostova, D., Bagdinov, A. V., Petrova, M. G., Demikhov, E. I., Pudonin, F. A., Dejneka, A.
Format: Article
Language:English
Subjects:
Applied physics
CHARGE CARRIERS
CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY
Current carriers
DEPOSITION
ELECTRON CORRELATION
ELLIPSOMETRY
EV RANGE 01-10
Localization
Spectroellipsometry
SPUTTERING
TANTALUM
TEMPERATURE COEFFICIENT
TEMPERATURE RANGE 0000-0013 K
TEMPERATURE RANGE 0013-0065 K
TEMPERATURE RANGE 0065-0273 K
TEMPERATURE RANGE 0273-0400 K
Thickness
Transport
Weight
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:We report the dc transport (5 K ≲ T ≲ 380 K) and spectroscopic ellipsometry (0.8 eV ≤ hν ≤ 8.5 eV, T ≃ 300 K) study of β-Ta films prepared by rf sputtering deposition as a function of their thickness in the range 2.5 nm ≲ d ≲ 200 nm. The dc transport of the β-Ta films with a thickness d ≳ 25 nm is characterized by negative temperature coefficient of resistivity (TCR) caused by localization effects peculiar of highly disordered metals. Their dielectric function spectra display non-metallic-like behavior due to the presence of the pronounced band at 2 eV. We found that with increasing TCR absolute value, specifying elevated degree disorder, the optical spectral weight (SW) of free charge carriers decreases. The associated SW is recovered in the range of Mott-Hubbard transitions, indicating the mechanism of localization enhancement by electronic correlations in disordered metals.
ISSN:0003-6951
1077-3118
DOI:10.1063/1.4907862