Work

Hall effect measurements on thermoelectric Ca3Co4O9: On how to determine the charge carrier concentration in strongly correlated misfit cobaltites

Year: 2015

Type: article

Abstract: The Hall coefficient RH and electrical conductivity of misfit calcium cobalt oxide (Ca2CoO3−δ)q(CoO2) (CCO) were measured at room temperature for different oxygen vacancy concentrations δ. Based on these and numerous previous results, it is shown that the charge carrier concentrations n obtained by the classical formula RH = 1/ne are between 3 and 6 × 1020 cm−3 and thereby much lower than those derived by other experimental techniques and fail to explain the observed electric properties of CCO. We show that the experimental results are well described using an earlier proposed t–J-model for strongly correlated electrons on a triangular lattice. The hopping parameter t for CCO was found to be ≈ −20 K and the charge carrier concentration of fully oxidized CCO to be 5.7 × 1021 cm−3 (0.41 hole type carriers per formula unit), in agreement with other experimental techniques.

Source: Journal of Applied Physics

DOI: 10.1063/1.4921861

Authors: Matthias Schrade, Truls Norby, Terje G. Finstad

Institution: University of Oslo

Language: English

Topic: Magnetic and transport properties of perovskites and related materials

Subfield: Electronic, Optical and Magnetic Materials

Field: Materials Science

Domain: Physical Sciences

Open Access status: green

Funder: Norges Forskningsråd

Awards: G1727517263, G2029465440, G6431734800