Revealing the Polaron State at the MoS₂/TiO₂ Interface

Area of Science:

• Materials Science
• Condensed Matter Physics
• Surface Science

Background:

• Interfacial polarons are crucial for charge distribution and properties in hybridized polaronic materials.
• Understanding these interactions is key to developing advanced functional materials.

Purpose of the Study:

• To investigate the electronic structures at the single-layer MoS2 (SL-MoS2) on rutile TiO2 interface.
• To elucidate the role of interfacial polarons in SL-MoS2/TiO2 systems.

Main Methods:

• High-resolution angle-resolved photoemission spectroscopy (ARPES) was used to probe electronic structures.
• Density functional theory (DFT) calculations corroborated experimental findings.

Main Results:

• Direct visualization of the valence band maximum and conduction band minimum (CBM) of SL-MoS2 at the K point.
• Determination of a direct bandgap of approximately 2.0 eV for SL-MoS2.
• Evidence of trapped electrons at the MoS2/TiO2 interface forming an interfacial Fröhlich polaron state by coupling with TiO2 phonons.

Conclusions:

• The CBM of MoS2 is significantly influenced by interfacial polaron formation.
• This interfacial coupling provides a novel strategy for tuning free charges in 2D material/metal oxide heterostructures.