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MM: Fachverband Metall- und Materialphysik

MM 19: Poster Session

MM 19.15: Poster

Dienstag, 10. März 2026, 18:00–20:00, P5

Anisotropic Thermoelectric Energy Converters Based on Bi Microwires and Films. — •Leonid Konopko¹, Albina Nikolaeva¹, Tito Huber², and Denis Shiversky¹ — ¹Technical University of Moldova, Chisinau, Moldova — ²Howard University, Washington, DC, USA

We demonstrate an innovative method for thermoelectric energy conversion utilizing a single-element device made from an anisotropic material. In such materials, heat flow generates a transverse thermoelectric electric field perpendicular to the direction of the heat transfer. For our experiments, we produced a sample using a 10-meter-long, glass-insulated, single-crystal tin-doped bismuth microwire (outer diameter - 20 µm; core diameter - 4 µm). A crucial aspect of this process was the successful growth of the microwire as a single crystal, achieved through laser-assisted recrystallization under a strong electric field. The microwire was coiled into a flat spiral and mounted onto a thin copper disk. This sample demonstrated high sensitivity to heat flow, reaching up to 10⁻² V/W, with a time constant of approximately 0.2 seconds. Bismuth films with thicknesses ranging from 2 to 5 µm were deposited onto mica substrates. Experimental samples of heat flux sensors were then fabricated by recrystallizing these films under laser heating in a strong electric field. The observed voltage dynamics at the output of all sensors, in response to modulated heat fluxes, align well with theoretical predictions for anisotropic thermoelectric elements.

The study was supported by the State Project "ReBRAIN" #25.80013.5007.07RE, 2025-2026.

Keywords: Thermoelectric Device; Anisotropic Thermoelement; Bismuth Single-crystal Microwire; Bi Single-crystal Film; Heat Flux Sensor