Thickness-Driven Modification of Interface States and Polarization Switching in MoTe₂/BaTiO₃ Heterostructures

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Van der Waals (vdW) ferroelectric heterostructures are crucial for studying interfacial phenomena and developing novel functionalities.
• Understanding and controlling interfacial electronic states is key to harnessing advanced properties in these systems.

Purpose of the Study:

• To investigate the effect of thickness engineering on interfacial states and polarization switching in 2H-MoTe₂/BaTiO₃ (BTO) heterostructures.
• To explore the relationship between band alignment, polarization fields, and defect traps in governing interfacial electronic structure.

Main Methods:

• Fabrication of 2H-MoTe₂/BaTiO₃ heterostructures with precise thickness control.
• Characterization of interfacial electronic structure using work function measurements and analysis of band alignment.
• Electrical transport measurements to probe conduction mechanisms under varying polarization states.

Main Results:

• A two-unit-cell thickness variation in MoTe₂ caused a significant work function shift (0.44 eV), reversing band alignment and doping polarity.
• This thickness-induced transition led to a deterministic reversal of BTO polarization (from P_up to P_down).
• Electrical transport evolved from trap-assisted conduction to Fowler-Nordheim tunneling, demonstrating robust multilevel nonvolatile memory characteristics.

Conclusions:

• Thickness-controlled interfacial states offer an effective strategy for tailoring ferroelectric switching dynamics.
• The findings provide a pathway for developing nonvolatile memory and neuromorphic computing applications.
• Deterministic polarization control achieved through thickness engineering opens new avenues in advanced electronic device design.