Temperature evolution of carrier density and mobility of PdSn2 semimetal: a magnetoresistance and Hall effect analysis

C.-C. Chang^1,2*, C.-N. Kuo^1,3,6, W.-T. Chen^3,4, C.-M. Cheng⁵, C.-K. Hong^1,3,6, Y.-R. Ou^1,3,6, C.-S. Lue^1,3,6, C.-L. Huang^1,2,3

¹Department of Physics, National Cheng Kung University, Tainan 70101, Taiwan
²Center for Quantum Frontiers of Research & Technology (QFort), National Cheng Kung University, Tainan 70101, Taiwan
³Taiwan Consortium of Emergent Crystalline Materials, National Science and Technology Council, Taipei 10622, Taiwan
⁴Center for Condensed Matter Sciences and Center of Atomic Initiative for New Materials, National Taiwan University, Taipei 10617, Taiwan
⁵National Synchrotron Radiation Research Center, Hsinchu 30076, Taiwan
⁶Program on Key Materials, Academy of Innovative Semiconductor and Sustainable Manufacturing, National Cheng Kung University, Tainan 70101, Taiwan

* Presenter:C.-C. Chang, email:L26104343@gs.ncku.edu.tw

A topological Insulator (TI) is a novel category of materials, defined through a continuous gap along the high symmetry points of the band structure around the Fermi level. PdSn₂ may be one of the TI candidates, as suggested by theoretical calculations. PdSn₂ crystallizes in a tetragonal structure with space group I4₁/acd. At room temperature, both magnetoresistance (MR) and Hall effect show hole-like single-band behavior under magnetic field. As the temperature decreases, the field dependence of MR and Hall effect shows curvature that hints the multiband nature of the Fermi surface. This implies that PdSn₂ exhibits semi-metallic behavior at low temperatures. Through a two-band analysis, we found a temperature evolution of the carrier density and mobility of this material. Such a shift of band structure under different temperatures may be probed by angle-resolved photoemission spectroscopy (ARPES). We will compare the ARPES results with the transport data, and, more interestingly, look for the signature of the surface state near the Fermi surface, a direct proof of TI.

Keywords: Hall effect, magnetoresistance, semimetal