Observation of Zero-Field Transverse Resistance in AlO_{x}/SrTiO_{3} Interface Devices

Area of Science:

• Condensed Matter Physics
• Materials Science
• Surface Science

Background:

• Two-dimensional carrier gases (2DGCs) at oxide interfaces exhibit complex electronic properties.
• Domain walls in ferroelectric materials like SrTiO_{3} (STO) can significantly influence charge transport.
• Understanding interfacial phenomena is crucial for novel electronic device applications.

Purpose of the Study:

• To investigate the emergence of a finite transverse resistance in AlO_{x}/STO heterostructures at low temperatures.
• To explore the dependence of this transverse resistance on domain wall configuration, temperature, and crystallographic orientation.
• To elucidate the underlying physical mechanisms responsible for the observed transport anomalies.

Main Methods:

• Fabrication of AlO_{x}/SrTiO_{3} heterostructures in Hall bar geometry.
• Electrical transport measurements, including Hall effect measurements in zero magnetic field.
• Temperature-dependent measurements from low temperatures up to room temperature.
• Capacitance measurements to probe the dielectric properties of STO.

Main Results:

• A finite transverse resistance, dependent on domain wall configuration, was observed in AlO_{x}/STO devices below 70 K.
• The transverse resistance exhibited significant changes below 40 K, correlating with domain wall polarization.
• Heterostructures with (111) orientation showed substantially larger transverse resistance compared to (001) orientation.
• The observed phenomenon was attributed to inhomogeneous current flow along domain walls.

Conclusions:

• Domain walls in AlO_{x}/STO interfaces introduce a novel transport signature: a magnetic-field-free transverse resistance.
• The anisotropic behavior and temperature dependence suggest a strong interplay between domain wall physics and electronic transport.
• The findings highlight the importance of domain wall engineering and crystallographic orientation for controlling charge transport in oxide heterostructures.