Charge transport in thin layer Na.sub.x./sub.CoO.sub.2./sub. (x similar to 0.63) studied by terahertz spectroscopy

0470137 - FZÚ 2017 RIV GB eng J - Journal Article
Němec, Hynek - Knížek, Karel - Jirák, Zdeněk - Hejtmánek, Jiří - Soroka, Miroslav - Buršík, Josef
Charge transport in thin layer Na_xCoO₂ (x similar to 0.63) studied by terahertz spectroscopy.
Journal of Physics-Condensed Matter. Roč. 28, č. 35 (2016), 1-6, č. článku 355601. ISSN 0953-8984. E-ISSN 1361-648X
R&D Projects: GA ČR GA13-17538S; GA ČR GA13-03708S; GA ČR GA13-12386S
Institutional support: RVO:68378271 ; RVO:61388980
Keywords : cobaltates * thermoelectrics * Na_xCoO₂ * terahertz spectroscopy
Subject RIV: BM - Solid Matter Physics ; Magnetism; CA - Inorganic Chemistry (UACH-T)
Impact factor: 2.678, year: 2016

Charge transport in Na0.63CoO2 thin film deposited by a spin-coating method was investigated experimentally by time-domain terahertz spectroscopy and theoretically using Monte Carlo calculations of charge response in nano-structured materials. The dominating type of transport mechanism over the entire investigated range of temperatures (20-300 K) is a metallic-like conductivity of charges partly confined in constituting nano-sized grains. Due to the granular character of our thin film, the scattering time at low temperatures is limited by scattering on grain boundaries and the conductivity is strongly suppressed due to capture of a major fraction of charge carriers in deep traps. Nevertheless, our experimental setup and the applied model allowed us to distinguish the parameters related to the grain interior from those influenced by grain boundaries, and to conclude that the metallic type of conductivity is the intrinsic property relevant to single crystal materials.
Permanent Link: http://hdl.handle.net/11104/0267859