Temperature-Driven Abrupt Changes in the Electronic Structure of 2D Si₂Te₃: A First-Principles Study

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Two-dimensional (2D) silicon telluride (Si2Te3) is a promising material due to its silicon compatibility and intrinsic p-type conductivity.
• Experimental studies indicate temperature-dependent optical and electrical properties in Si2Te3, potentially linked to Si-Si dimer orientations.
• The precise mechanism governing these property changes remains unclear.

Purpose of the Study:

• To investigate the influence of Si-Si dimer orientations on the electronic structure of Si2Te3.
• To elucidate the fundamental mechanisms behind the observed temperature-dependent properties.

Main Methods:

• First-principles density functional theory (DFT) calculations were employed.
• The study focused on analyzing the electronic band structure and effective mass variations.

Main Results:

• Si-Si dimer configurations were found to induce transitions between direct and indirect band gaps.
• Significant alterations in hole effective mass were observed based on dimer orientation.
• A direct correlation between Si-Si dimer orientation and electronic properties was established.

Conclusions:

• The orientation of Si-Si dimers is a critical factor determining the electronic and optical properties of Si2Te3.
• These findings provide fundamental insights into Si2Te3's behavior.
• The results guide the future design and application of Si2Te3-based devices.