High mobility conduction at (110) and (111) LaAlO3/SrTiO3 interfaces

Area of Science:

• Solid State Physics
• Materials Science
• Condensed Matter Physics

Background:

• Two-dimensional electron liquids (2DEL) exhibit high mobility transport at oxide interfaces.
• Previously, only the (001) surface of strontium titanate (SrTiO3) was known to host 2DEL.
• This limitation posed challenges for understanding and engineering these emergent properties.

Purpose of the Study:

• To investigate if 2DEL transport can be achieved on other SrTiO3 surfaces.
• To explore alternative interface configurations beyond epitaxial growth.
• To broaden the scope of materials research for oxide electronics.

Main Methods:

• Fabrication of interfaces between SrTiO3 and LaAlO3 layers on (110) and (111) oriented substrates.
• Characterization of transport properties, including mobility measurements.
• Investigation of interfaces with amorphous LaAlO3 and other oxides.

Main Results:

• Two-dimensional electron liquids (2DEL) were successfully engineered on (110) and (111) SrTiO3 surfaces.
• These interfaces exhibited high carrier mobilities comparable to the (001) surface.
• Conducting interfaces were also formed using amorphous LaAlO3 and other oxides, not requiring epitaxy.

Conclusions:

• The restriction of 2DEL to specific oxide interfaces is surpassed.
• New avenues for materials design and the study of carrier doping mechanisms are opened.
• This expands the potential for novel oxide electronic devices.