Large linear magnetoresistance in heavily-doped Nb:SrTiO3 epitaxial thin films

Abstract

Interaction between electrons has long been a focused topic in condensed-matter physics since it has led to the discoveries of astonishing phenomena, for example, high-Tc superconductivity and colossal magnetoresistance (CMR) in strongly-correlated materials. In the study of strongly-correlated perovskite oxides, Nb-doped SrTiO3 (Nb:SrTiO3) has been a workhorse not only as a conducting substrate, but also as a host possessing high carrier mobility. In this work, we report the observations of large linear magnetoresistance (LMR) and the metal-to-insulator transition (MIT) induced by magnetic field in heavily-doped Nb:STO (SrNb0.2Ti0.8O3) epitaxial thin films. These phenomena are associated with the interplay between the large classical MR due to high carrier mobility and the electronic localization effect due to strong spin-orbit coupling, implying that heavily Nb-doped Sr(Nb0.2Ti0.8)O3 is promising for the application in spintronic devices.

From Low-Field Sondheimer Oscillations to High-Field Very Large and Linear Magnetoresistance in a SrTiO3-Based Two-Dimensional Electron Gas

“…A few studies also mention a linear magnetoresistance (MR) for perpendicular magnetic field B , with, in some cases, a very large amplitude (>500% at 9 T) . This is reminiscent of a giant, nonsaturating linear MR reported in various systems including narrow band gap semiconductors, graphene, , semimetals, − and topological insulators. , Two main scenarios have been proposed to explain this behavior.…”

Dependence of the inverse spin Hall effect in Sr(NbxTi1−x)OZhang1, Zhang2, Peng3 et al. 2020Physica B: Condensed Matter

“…The carrier effective mass (m * ) is about 7 times larger than that of the free electrons which comes from the d−orbitals. Large linear magnetoresistance (MR) was observed due to the combination of the interplay between the large classical MR due to high carrier mobility and the electronic localization effect due to strong SOC 14 . The Nb concentration dependent SOC was further investigated 15 , which shows a proportionality.…”

From low-field Sondheimer oscillations to high-field very large and linear magnetoresistance in a SrTiO$_3$-based two-dimensional electron gas

“…6 A peculiar angular dependence of the resistance, including a unidirectional magnetoresistance 7,8 and high order oscillations, 9 has also been reported. 8,[10][11][12] A few studies also mention a linear magnetoresistance (MR) for perpendicular magnetic field B 13,14 with, in some cases, a very large amplitude (>500% at 9 T). 13 This is reminiscent of a giant, non-saturating linear MR reported in various systems including narrow bandgap semiconductors, 15 graphene, 16,17 semimetals, [18][19][20] and topological insulators.…”

“…8,[10][11][12] A few studies also mention a linear magnetoresistance (MR) for perpendicular magnetic field B 13,14 with, in some cases, a very large amplitude (>500% at 9 T). 13 This is reminiscent of a giant, non-saturating linear MR reported in various systems including narrow bandgap semiconductors, 15 graphene, 16,17 semimetals, [18][19][20] and topological insulators. 21,22 Two main scenarios have been proposed to explain this behavior.…”