2D Small Hole Polarons in Ga₂O₃

Area of Science:

• Materials Science
• Condensed Matter Physics
• Computational Materials Science

Background:

• Holes in oxides like gallium oxide (Ga2O3) are known to localize and distort the lattice, forming small polarons.
• Previous research has established the phenomenon of polaron formation in bulk oxide materials.

Purpose of the Study:

• To investigate the formation and characteristics of polarons in experimentally demonstrated (100) Ga2O3 nanolayers.
• To determine the preferred localization sites for polarons within the Ga2O3 nanostructure.

Main Methods:

• Utilized density functional theory (DFT) calculations at the hybrid functional level.
• Simulated polaron formation in 2D (100) Ga2O3 nanolayers.

Main Results:

• Polarons can localize on oxygen atoms in Ga2O3 nanolayers.
• Two distinct 3-fold coordinated oxygen sites result in stable polarons.
• A 4-fold coordinated oxygen site leads to a metastable polaron, involving Ga-O bond breaking and significant Ga atom displacement.

Conclusions:

• The study identifies specific oxygen sites responsible for stable and metastable polaron formation in Ga2O3 nanolayers.
• The predicted large atomic displacement for metastable polarons suggests a pathway for experimental observation using high-resolution transmission electron microscopy (HRTEM).