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

0449091 - FZÚ 2016 RIV US eng J - Journal Article
Kovaleva, Natalia - Chvostová, Dagmar - Bagdinov, A.V. - Petrova, M.G. - Demikhov, E.I. - Pudonin, F.A. - Dejneka, Alexandr
Interplay of electron correlations and localization in disordered β-tantalum films: evidence from dc transport and spectroscopic ellipsometry study.
Applied Physics Letters. Roč. 106, č. 5 (2015), "051907-1"-"051907-5". ISSN 0003-6951. E-ISSN 1077-3118
R&D Projects: GA ČR GA15-13778S
Institutional support: RVO:68378271
Keywords : diffusion * absence
Subject RIV: BM - Solid Matter Physics ; Magnetism
Impact factor: 3.142, year: 2015

We report the dc transport (5K less than or similar to T less than or similar to 380 K) and spectroscopic ellipsometry (0.8 eV <= h nu <= 8.5 eV, T similar or equal to 300 K) study of beta-Ta films prepared by rf sputtering deposition as a function of their thickness in the range 2.5 nm less than or similar to d less than or similar to 200 nm. The dc transport of the beta-Ta films with a thickness d greater than or similar to 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.
Permanent Link: http://hdl.handle.net/11104/0250678