Przemysław Swatek | Searcharxiv

arXiv2018

Magnetoresistance in YBi and LuBi semimetals due to nearly perfect carrier compensation

Monobismuthides of yttrium and lutetium are shown as new representatives of materials which exhibit extreme magnetoresistance and magnetic-field-induced resistivity plateau. At low temperatures and in magnetic field of 9T the magnetoresistance attains the order of magnitude of 10,000% and 1,000%, on YBi and LuBi, respectively. Our thorough examination of electron transport properties of both compounds show that observed features are the consequence of nearly perfect carrier compensation rather than of possible nontrivial topology of electronic states. The field-induced plateau of electrical resistivity can be explained with Kohler scaling. Anisotropic multi-band model of electronic transport describes very well the magnetic field dependence of electrical resistivity and Hall resistivity. Data obtained from the Shubnikov-de Haas oscillations analysis also confirm that Fermi surface of each compound contains almost equal amounts of holes and electrons. First-principle calculations of electronic band structure are in a very good agreement with the experimental data.

cond-mat.mtrl-sci↗

arXiv2016

Giant magnetoresistance, three-dimensional Fermi surface and origin of resistivity plateau in YSb semimetal

Very strong magnetoresistance and a resistivity plateau impeding low temperature divergence due to insulating bulk are hallmarks of topological insulators and are also present in topological semimetals where the plateau is induced by magnetic field, when time-reversal symmetry (protecting surface states in topological insulators) is broken. Similar features were observed in a simple rock-salt-structure LaSb, leading to a suggestion of the possible non-trivial topology of 2D states in this compound. We show that its sister compound YSb is also characterized by giant magnetoresistance exceeding one thousand percent and low-temperature plateau of resistivity. We thus performed in-depth analysis of YSb Fermi surface by band calculations, magnetoresistance, and Shubnikov--de Haas effect measurements, which reveals only three-dimensional Fermi sheets. Kohler scaling applied to magnetoresistance data accounts very well for its low-temperature upturn behavior. The field-angle-dependent magnetoresistance demonstrates a 3D-scaling yielding effective mass anisotropy perfectly agreeing with electronic structure and quantum oscillations analysis, thus providing further support for 3D-Fermi surface scenario of magnetotransport, without necessity of invoking topologically non-trivial 2D states. We discuss data implying that analogous field-induced properties of LaSb can also be well understood in the framework of 3D multiband model.

cond-mat.mtrl-sci↗