Applying four coefficient transport measurements to strongly correlated electron systems

The direct experimental determination of transport relevant parameters, such as effective mass and scattering time, is conventionally achieved using Shubnikov de Haas oscillations, which occur in the limit of high magnetic fields. In strongly correlated electron systems the conduction band width is usually narrow and the strong electron-electron interaction results in a mass enhancement, making it difficult to fulfill this criteria. An elegant way out of the dilemma is the determination of the four transport coefficients resistivity (ρ), Seebeck (α), Nernst (Q), and Hall (R_H) to determine transport relevant parameters¹. We report on an experimental setup to determine these four transport coefficients, which has been integrated into a PPMS system. The validity of the measurements is shown by analyzing Al-doped ZnO and Sn-doped In₂O₃¹, and then utilized to determine effective carrier mass and scattering time from the strongly correlated metal SrVO₃ as a function of temperature.

¹D.L. Young, et al, Direct Measurement of Density-of-States Effective Mass and Scattering Parameter in Transparent Conducting Oxides Using Second-Order Transport Phenomena, 1-18, (2000)