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

Abstract

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.

Presence of exotic electronic surface states in LaBi and LaSb

“…Recently, the lanthanum monopnictides LaX (X = P, As, Sb and Bi) were predicted to be topological insulators 22 . This inspired an explosion of mainly transport work on LaSb [23][24][25] , LaBi 23,[26][27][28][29] , and YSb [30][31][32] , all of which crystallize in the well-known NaCl structure. All show a large unsaturated magnetoresistance, which is often attributed to the quantum limit of the Dirac fermions 33 , but may also arise from complicated factors such as electron-hole compensation 34,35 .…”

Separation of electron and hole dynamics in the semimetal LaSb

“…Other mechanisms such as a magnetic-field induced metal-insulator transition (MIT) [28][29][30][31][32][33], electron-hole (e-h) compensation [12,18,27,34], and forbidden backscattering at zero field [15] have also been considered as possible origins for XMR. Recently, the rare-earth monopnictides LnX (Ln = La/Y/Nd/Ce and X = Sb/Bi) [27,[34][35][36][37][38][39][40][41][42][43][44][45][46][47][48][49] were added to the family of XMR materials. These materials, with a rock-salt cubic crystal lattice, exhibit typical hallmark XMR behavior such as power-law magnetoresistance and magnetic-field induced turn-on behavior as a function of temperature.…”

Origin of exceptional magneto-resistance in Weyl semimetal TaSb2

“…Quite generally, the study of electrical resistance in the presence of external magnetic field renders deep insight into electronic transport mechanism [10] that collaterally leads to several technological applications such as in magnetic sensors, magnetic switches and magnetic storage devices. To bring in a prospective, the reported [6,[11][12][13][14][15][16][17][18][19] magnetoresistance in TSMs could be two orders of magnitude higher than the giant magnetoresistance (GMR) or colossal magnetoresistance (CMR) observed in metallic thin films [20], perovskite manganites [21] or Cr-based chalcogenide spinels [22]. At the core of such exceptional magneto-resistance is the peculiar band structure of three-dimensional TIs and TSMs that yields conducting surface states.…”