Transport properties and thermal behavior of YbMnSb2 semimetal above room temperature

Highlights: • Experimental studies on a layered antimonide YbMnSb₂ with high Seebeck coefficient. • YbMnSb₂ is air-stable but decomposes at high temperature. Thermal analysis indicates that it incongruently melts at ca. 1020 K. • High thermopower and low resistivity suggest suitability for thermoelectric applications in the mid-temperature region. Single crystals of ytterbium manganese diantimonide, YbMnSb₂ have been grown from a high-temperature reaction of the elements, employing molten Sb as self-flux. This phase crystallizes in the tetragonal centrosymmetric space group P4/nmm (No. 129) and adopts the ZrCuSiAs structure type. The structure consists of Sb-based square nets and PbO-type layers formed by fused [MnSb_4/4] tetrahedra. YbMnSb₂ is stable under ambient atmosphere and incongruently melts at a temperature of ca. 1120 K. In the temperature range from 300K to 450K, the electrical resistivity of the as-grown single-crystalline material is as low as 3.2mΩcm, while its thermopower is as high as 180μV/K. As such, YbMnSb₂ shows promise for thermoelectric applications in the mid-temperature region, with an estimated power factor of 0.85–0.95 mW/(m K²).