β-As Monolayer: Vibrational Properties and Raman Spectra

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• V-group element monolayers exhibit unique semiconducting properties.
• Antimonene and black phosphorus pave the way for arsenic monolayers as 2D semiconductors.

Purpose of the Study:

• Investigate the vibrational properties and Raman spectra of buckled honeycomb arsenic monolayers (β-As).
• Determine polarization-dependent Raman intensities for various laser lines.
• Provide insights for experimental identification and orientation of β-As monolayers.

Main Methods:

• Density Functional Theory (DFT) calculations.
• Calculation of Raman tensor for active modes.
• Analysis of polarization angle-dependent Raman intensities.

Main Results:

• Identified two nonresonant Raman peaks at 235 cm⁻¹ (E<0xE2><0x82><0x91>) and 305 cm⁻¹ (A<0xE2><0x82><0x81><0xE2><0x82><0x91>).
• Observed distinct polarization-dependent Raman intensity patterns (minima and maxima) based on incident light polarization and wave vector orientation.
• Found Raman intensities generally decrease with increasing laser wavelength.
• Established a relationship between polar plot shapes and Raman tensor elements.

Conclusions:

• The vibrational and Raman spectra of β-As monolayers are characterized.
• Polarization-dependent Raman spectroscopy can be used to identify and orient β-As monolayers.
• Results offer guidance for experimental synthesis and characterization of arsenic monolayers.