Observation of Shubnikov–de Haas Oscillations, Planar Hall Effect, and Anisotropic Magnetoresistance at the Conducting Interface of EuO–KTaO₃

Abstract

The momentum‐dependent splitting of spin‐bands in an electronic system is known as the “Rashba effect.” Systems with the Rashba effect possess a Dirac point in momentum space, which may act as a source of Berry's phase for the conduction electrons of such system. Herein, the Shubnikov–de Haas oscillations (SdH) at the conducting interface of EuO–KTaO3 (KTO) are reported. The observed SdH oscillations suggest the presence of two Fermi surfaces. For both Fermi surfaces, the presence of a Berry's phase is seen. Strong spin–orbit coupling is also observed in this system. The existence of two Fermi surfaces with Berry's phase along with the signature of strong spin–orbit coupling suggest the formation of Rashba spin‐split bands. As in topological insulators, two‐fold planar Hall effect and anisotropic magnetoresistance are also observed in EuO–KTO. Analyzing the SdH, Hall, and magnetoresistance data, the authors draw a possible band diagram near the Fermi surface.

KTaO3—The New Kid on the Spintronics Block

“…It appears that a recent strategy to use KTO as a substrate rather than a film may prove to be the game‐changer, as the resulting interface may be expected to exhibit exciting electronic and magnetic properties due to the strong SOC. [ 45,46 ] This could therefore open the door for the development of the next generation of devices based on “spin‐opto‐electronics.” Based on their observed properties and current research trends, we may realistically anticipate applications of KTO‐based structures not only in 2DEG field effect transistors (FETs) and spin transistors, but possibly also in other, high‐end devices. These may include electrical and optical memories, ultralow‐field magnetic and electrostatic sensors, and various thermo‐electric, optoelectronic, and photovoltaic devices.…”

“…[ 66 ] A KTO‐based 2DEG was first realized at the LTO–KTO interface, [ 67 ] followed by more interesting observations in LAO–KTO, [ 68,69 ] LVO–KTO, [ 45,70 ] and EuO–KTO. [ 46,71 ] Furthermore, KTO‐based systems were found to exhibit several emergent physical properties that are fascinating not only from the point of view of fundamental physics but could also find applications in future‐generation spin‐electronics devices. The 2DEG at the interface of (001)‐oriented EuO–KTO shows a high degree of spin polarization that is manifested as negative MR (NMR) and anomalous Hall effect (AHE).…”

A Case Study to Address: “Is Your Pulsed Laser Deposition Chamber Clean?”

“…[ 7 ] Such 2DEG exhibits exciting properties like quantum hall effect, coexistence of superconductivity and magnetism, Shubnikov–de Hass oscillations, planar Hall effect, persistent photoconductivity and so on. [ 8–15 ] Since then a large number of articles have been reported on perovskite oxide thin films, interfaces and superlattices, exhibiting integrated and emergent physical properties.…”

Tuning the Electrical State of 2DEG at LaVO3−KTaO3 Interface: Effect of Light and Electrostatic Gate

“…Recently, KTaO 3 (KTO) has drawn tremendous interest since it has demonstrated the possibility of hosting low‐dimensional electron gas with high electron mobility and strong spin−orbit coupling, approximately one order of magnitude larger than STO. [ 40,41 ] These observations promote KTO as a promising candidate for spintronic applications. [ 42 − 44 ] These are quite recent observations and only a few interfaces of KTO have shown to host highly mobile electron gas, namely interface of LTO−KTO, amorphous−LAO−KTO, LaVO 3 (LVO)−KTO, and EuO−KTO.…”

“…[ 42 − 44 ] These are quite recent observations and only a few interfaces of KTO have shown to host highly mobile electron gas, namely interface of LTO−KTO, amorphous−LAO−KTO, LaVO 3 (LVO)−KTO, and EuO−KTO. [ 40,41,45,46 ]…”