Conduction of heat in a material via heat currents is a phenomenon analogous to charge transport via electrical currents. Thermoelectric phenomena arise from the entanglement of thermal and electrical transport processes due to (1) heat transport by charge carriers and (2) scattering processes between charge carriers and other heat-carrying quasiparticles, e.g. phonons. By studying the thermal conductivity κ, the thermopower S and the Nernst coefficient N at low temperatures and magnetic fields, we gain valuable information on charge and heat carriers and low energy excitations. [more]

In high carrier density correlated electron systems, quantum oscillations are usually detected as tiny oscillations of the magnetization of a sample that appear below 1K. This requires extremely precise and low noise measurement techniques. We have developed a magnetometer based on piezoresistive cantilevers for submilimeter-sized samples with a resolution that is 10-20 times better than previous techniques at 700 mK and in strong magnetic fields. The working principle is based on the use of a SQUID as a low temperature amplifier, which we were able to run in fields up to 15T. [more]