Design and implementation of a high-precision angle-resolved thermoelectric measurement apparatus

This work reports the development of a homemade thermoelectric measurement apparatus designed for in situ angle-resolved transport studies under cryogenic temperatures and high magnetic fields. The system employs a chip resistor as a heater to establish a stable longitudinal temperature gradient (ΔT), where ΔT denotes the temperature difference across the sample, while a Type-E thermocouple is integrated for temperature-difference monitoring. A key feature of this design is the integration of the measurement assembly onto a Physical Property Measurement System rotator probe, enabling precise stepwise modulation of the magnetic-field orientation relative to the sample's crystallographic axes under high-vacuum conditions. The apparatus achieves a low noise floor, resolving Seebeck and Nernst signals with fluctuations confined to approximately ±10 nV/K, and its accuracy and the associated sources of measurement error are characterized using a Constantan reference sample. The setup is further demonstrated through angle-dependent measurements on ZrTe5 and BiSbTeSe2 (BSTS2) single crystals, highlighting the applicability of this methodology for investigating thermoelectric transport properties of topological and functional materials.