Enhanced Nonlinear Response by Manipulating the Dirac Point at the (111) LaTiO_{3}/SrTiO_{3} Interface

Area of Science:

• Condensed Matter Physics
• Materials Science
• Spintronics

Background:

• Tunable spin-orbit interaction (SOI) is crucial for spintronic devices.
• SOI can induce energy band asymmetry, leading to nonlinear transport phenomena (V~I^2).
• The (111) LaTiO3/SrTiO3 interface offers a single-band Hall response, ideal for studying SOI effects.

Purpose of the Study:

• Investigate the role of SOI in nonlinear transport at the (111) LaTiO3/SrTiO3 interface.
• Analyze the influence of magnetic fields on SOI-induced nonlinear transport.
• Understand the mechanism behind magnetic field-dependent nonlinear resistance.

Main Methods:

• Experimental measurements of nonlinear longitudinal resistance.
• Application of in-plane and out-of-plane magnetic fields.
• Theoretical analysis based on the Dirac point location and Fermi contour symmetry.

Main Results:

• A significant increase in nonlinear longitudinal resistance was observed at a critical in-plane magnetic field (Hcr).
• The observed rise in nonlinear resistance diminished with the introduction of an out-of-plane magnetic field component.
• The behavior was explained by the magnetic field's influence on the Dirac point position relative to the Fermi contour.

Conclusions:

• The position of the Dirac point, determined by magnetic field orientation, critically affects nonlinear transport.
• In-plane magnetic fields enhance nonlinear transport by shifting the Dirac point away from the Fermi contour.
• Out-of-plane magnetic fields suppress nonlinear effects by gapping the Dirac point, offering a unified explanation for related magnetoresistance phenomena.