First-Principles Calculations for Enhancing the TER Effect through Resonance Band Engineering

Area of Science:

• Materials Science
• Condensed Matter Physics
• Quantum Mechanics

Background:

• Ferroelectric tunnel junctions (FTJs) exhibit tunneling electroresistance (TER), a property crucial for electronic devices.
• Enhancing TER is key to improving FTJ performance for applications.
• Existing methods for TER enhancement include resonant band engineering and asymmetric electrodes.

Purpose of the Study:

• To investigate the enhancement of TER in FTJs using a combination of resonant band engineering and asymmetric electrodes.
• To explore the effect of a composite tunneling barrier (BaTiO3 with BaSnO3 substitutions) on TER.
• To achieve a significant enhancement in the TER effect for potential device applications.

Main Methods:

• First-principles modeling based on density functional theory (DFT).
• Investigation of FTJs with asymmetric electrodes (Pt and SrRuO3) and a composite BaTiO3/BaSnO3 tunneling barrier.
• Analysis of ferroelectric polarization effects on band structure and resonant tunneling.

Main Results:

• Ferroelectric polarization in BaTiO3 shifts the conduction band minimum of BaSnO3 below the Fermi energy, inducing resonant tunneling.
• The combination of resonant tunneling and barrier height modulation by asymmetric electrodes significantly enhances the TER effect.
• Achieved a remarkable TER effect of 10^6% in the engineered FTJ.

Conclusions:

• Resonant band engineering coupled with asymmetric electrodes is an effective strategy for enhancing FTJ performance.
• The proposed composite barrier design offers a viable pathway for achieving high TER values.
• This research provides a promising approach for developing next-generation electronic devices based on FTJs.