Large Linear Magnetoresistance of High‐Mobility 2D Electron System at Nonisostructural γ‐Al₂O₃/SrTiO₃ Heterointerfaces

Abstract

Materials with a large linear magnetoresistance (MR) are great candidates for magnetic sensors, but rarity boosts investigations for exploring this MR in material physics. 2D electron system (2DES) formed at the nonisostructural heterointerfaces between γ‐Al2O3 (GAO) and SrTiO3 (STO) provides plenty of intriguing or even superior emergent properties compared with the conventional isomorphic all‐perovskite counterparts. Herein, a large MR exceeding 2000% in magnitude at the magnetic GAO/STO heterointerfaces with a high carrier mobility of 30 000 cm2 V−1 s−1 at low temperature is demonstrated. In contrast to the quadratic dependence on the magnetic field of the conventional oxide 2DES, MR in GAO/STO is linear and nonsaturating at high fields, which is stemmed from the magnetic inhomogeneities‐induced inhomogeneous conductivities. In addition, weak antilocalization effect gives rise to an extra quantum correction to the MR in low‐field region. Furthermore, a general qualitative picture of MR proportional to the mobility is established. These findings reveal the nonisostructural GAO/STO heterointerface is of great promise in magnetic sensor‐based practical memory applications and transistor designs.

Linear nonsaturating magnetoresistance in kagome superconductor CsV3Sb5 thin flakes

“…Linear nonsaturating magnetoresistance (LMR) is an unconventional transport phenomenon that the longitudinal electrical resistivity of the material increases linearly with external magnetic field (B). LMR is scientifically interesting [1][2][3][4][5][6] and potentially useful in applications such as magnetic sensors [7][8][9], attracting considerable attention from the materials science community. LMR materials include narrow band-gap disordered semiconductors [1,7,8,[10][11][12][13], topological semi-metals with linear dispersion relation [2,4,14,15], various materials with charge/spin density wave (CDW/SDW) orders [16][17][18], and high-T c superconductors [6].…”

Two‐Dimensional Electron Gases at the Amorphous and Crystalline SrTiO3/KTaO3 Heterointerfaces

“…The nonlinear Hall behavior (R xy -B) of the a-STO/KTO 2DEG reveals that there are two-type charge carriers contributing to the transport properties. [34] The mobility and density of the two kinds of charge carriers are analyzed and deduced by fitting the experimental data R xy (B), using the two-band model [15,[34][35][36]…”

“…The nonlinear Hall behavior ( R xy ‐B ) of the a‐STO/KTO 2DEG reveals that there are two‐type charge carriers contributing to the transport properties. [ 34 ] The mobility and density of the two kinds of charge carriers are analyzed and deduced by fitting the experimental data R xy (B) , using the two‐band model [ 15,34–36 ] with the constraint of…”

Enhanced Rashba Spin Orbit Coupling and Magnetic Behavior at Oxide Heterointerfaces by Optical Gating

“…Among these appealing properties of interfacial 2DEG, the magnetism is a strongly desired one, , as it provides a powerful platform to study the spintronics in all-oxide devices. − To date, there have been many meaningful works to generate magnetic 2DEGs at the interfaces of complex oxides, like to use a magnetic substrate or capping layer, , to introduce magnetic dopants, , or to insert a magnetic buffer layer into the interface. − These works broaden our horizon in condensed matter physics. In the all-oxide interfacial 2DEGs, the most important and irrefutable fingerprint of magnetism is the anomalous Hall effect ( AHE ), which was first reported by Joshua et al and then discussed by many subsequent works. − To manipulate it, many external stimuli, like light, strain, and electric field, can be available choices, − since they have shown their capabilities in adjusting other properties in all-oxide 2DEGs, like magnetoresistance ( MR ), mobility, etc. Among these methods, light has been playing a very important role in many fields, − as the multifield responding devices require correlation between diverse features, like that between light and magnetism.…”