Revealing the charge transport physics in metallic coordination nanosheets by thermoelectric and magnetotransport measurements

Abstract

We have studied the charge transport physics of high-quality conducting coordination nanosheets films based on the benchmark material copper benzenehexathiol (CuBHT) by measuring multiple thermoelectric and magnetotransport coefficients on the same film. The films exhibit a metallic temperature dependence of the conductivity over a wide temperature range, but below 15 kelvin charge transport becomes dominated by weak localization and electron-electron interactions. Temperature-dependent Hall, Seebeck, and Nernst measurements consistently indicate the existence of ambipolar transport characteristics in CuBHT. A two-band analysis has been used to extract transport parameters for electron and hole carriers as a function of temperature. The results show that contributions from electron and hole conduction in CuBHT are of comparable magnitude, revealing the complexity of charge transport and allowing one to identify strategies for enhancing the thermoelectric transport coefficients of such conducting coordination nanosheets.