Evidence of linear and cubic Rashba effect in non-magnetic heterostructure.

Area of Science:

• Condensed Matter Physics
• Materials Science
• Surface Science

Background:

• Interfaces between complex oxides can exhibit emergent electronic properties.
• Spin-orbit coupling (SOC) significantly influences electronic band structures.
• LaAlO3/KTaO3 is a promising system for investigating interfacial phenomena.

Purpose of the Study:

• To systematically investigate the electronic properties of defect-free (001) LaAlO3/KTaO3 interfaces.
• To analyze the impact of spin-orbit coupling on the interfacial electronic states.
• To identify potential applications, such as photocurrent generation.

Main Methods:

• First-principles calculations were employed.
• Two distinct interface types, Type-I and Type-II, were studied.
• Electronic band structures and spin interactions were analyzed.

Main Results:

• Type-I heterostructure exhibits a two-dimensional (2D) electron gas with cubic and linear Rashba interactions.
• Type-II heterostructure hosts an oxygen-rich 2D hole gas with linear Rashba-type spin-splitting in both valence and conduction bands.
• Type-II interface shows potential for photocurrent generation, relevant to the circularly polarized photogalvanic effect.

Conclusions:

• The LaAlO3/KTaO3 system demonstrates diverse interfacial electronic behaviors based on interface termination.
• SOC plays a crucial role in inducing distinct spin textures and electronic gases.
• The Type-II interface is a promising platform for exploring optoelectronic phenomena.