First-principles study of bipolar resistive memories based on monolayerα-GeTe

Area of Science:

• Materials Science
• Condensed Matter Physics
• Computational Materials Science

Background:

• Monolayer materials offer unique electronic properties.
• Resistive random-access memory (RRAM) requires novel materials for improved performance.
• Germanium telluride (GeTe) is a promising material for electronic devices.

Purpose of the Study:

• Investigate the electrical properties of monolayer alpha-germanium telluride (ML α-GeTe).
• Explore the potential of graphene/ML α-GeTe heterostructures for RRAM applications.
• Understand the mechanism behind the observed electrical characteristics and optimize device performance.

Main Methods:

• First-principles calculations to study electrical properties of ML α-GeTe.
• Analysis of potential distribution and band structure to explain anisotropy and nonlinearity.
• Construction and stability calculation of graphene/ML α-GeTe interfaces using binding energy and Mulliken population.
• Fabrication of graphene/ML α-GeTe/graphene devices and calculation of current-voltage (IV) characteristics.

Main Results:

• Armchair α-GeTe exhibits ohmic behavior, while zigzag α-GeTe shows nonlinear current.
• Relatively stable interfaces (GC3 and TC3) were identified for graphene and ML α-GeTe.
• The GR/ML α-GeTe/GR device demonstrates bipolar resistance characteristics with suitable set/reset voltages and a high window value (10^4).
• Resistance mechanism is attributed to the drift of Te vacancies forming conductive filaments, with performance enhanced by Te vacancy creation.

Conclusions:

• Graphene/ML α-GeTe/graphene heterostructures show potential for high-performance RRAM.
• The study provides insights into the electrical properties and resistance mechanisms of ML α-GeTe based devices.
• The findings are valuable for the design and application of novel RRAM devices.