TY - JOUR
AU - J Ravichandran
AU - A.K Yadav
AU - W Siemons
AU - M.A McGuire
AU - V Wu
AU - A Vailionis
AU - A Majumdar
AU - Ramamoorthy Ramesh
AB - We investigated size effects on thermoelectricity in thin films of a strongly correlated layered cobaltate. At room temperature, the thermopower is independent of thickness down to 6 nm. This unusual behavior is inconsistent with the Fuchs-Sondheimer theory, which is used to describe conventional metals and semiconductors, and is attributed to the strong electron correlations in this material. On the other hand, the resistivity increases below a critical thickness of ∼30 nm, as expected. The temperature-dependent thermopower is similar for different thicknesses but the resistivity shows systematic changes with thickness. Our experiments highlight the differences in thermoelectric behavior of strongly correlated and uncorrelated systems when subjected to finite-size effects. We use the atomic-limit Hubbard model at the high-temperature limit to explain our observations. These findings provide new insights into decoupling electrical conductivity and thermopower in correlated systems. © 2012 American Physical Society.
BT - Physical Review B - Condensed Matter and Materials Physics
DO - 10.1103/PhysRevB.85.085112
LA - eng
M1 - 8
N1 - cited By 14
N2 - We investigated size effects on thermoelectricity in thin films of a strongly correlated layered cobaltate. At room temperature, the thermopower is independent of thickness down to 6 nm. This unusual behavior is inconsistent with the Fuchs-Sondheimer theory, which is used to describe conventional metals and semiconductors, and is attributed to the strong electron correlations in this material. On the other hand, the resistivity increases below a critical thickness of ∼30 nm, as expected. The temperature-dependent thermopower is similar for different thicknesses but the resistivity shows systematic changes with thickness. Our experiments highlight the differences in thermoelectric behavior of strongly correlated and uncorrelated systems when subjected to finite-size effects. We use the atomic-limit Hubbard model at the high-temperature limit to explain our observations. These findings provide new insights into decoupling electrical conductivity and thermopower in correlated systems. © 2012 American Physical Society.
PY - 2012
T2 - Physical Review B - Condensed Matter and Materials Physics
TI - Size effects on thermoelectricity in a strongly correlated oxide
VL - 85
SN - 10980121
ER -