Direct Observation of Two-Dimensional Electron Gas with Low Effective Mass in Atomically Thin InTe

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Atomically thin InTe, a III-VI semiconductor analogous to InSe, is a potential candidate for nanoelectronic devices.
• The existence and properties of its two-dimensional electron gas (2DEG) have not been experimentally confirmed.

Purpose of the Study:

• To provide direct experimental evidence for the 2DEG in monolayer and bilayer InTe.
• To characterize the electronic band structure and effective mass of electrons in these materials.

Main Methods:

• Scanning tunneling microscopy (STM) for real-space imaging.
• Quasiparticle interference (QPI) imaging to probe electronic band structure.
• Density functional theory (DFT) calculations for theoretical validation.

Main Results:

• Direct evidence of a 2DEG in both monolayer and bilayer InTe was observed.
• Parabolic conduction-band dispersion was identified in both thicknesses.
• Monolayer InTe shows a low electron effective mass (0.241 me), lower than InSe and BLG.
• Bilayer InTe exhibits two subbands due to interlayer coupling with effective masses of 0.197 me and 0.802 me.

Conclusions:

• Atomically thin InTe hosts a 2DEG with tunable electronic properties.
• The low effective mass in monolayer InTe is advantageous for high-performance nanoelectronics.
• Interlayer coupling in bilayer InTe leads to distinct subband structures.
• These findings position InTe as a significant material for future low-dimensional electronic applications.