Chiral Covalent Organic Framework for Highly Efficient Spin Polarization.

Area of Science:

• Materials Science
• Organic Chemistry
• Condensed Matter Physics

Background:

• Two-dimensional chiral covalent organic frameworks (2D-CCOFs) offer potential for chiral spintronic applications due to tunable semiconducting properties and inherent chirality.
• Key challenges include synthesizing highly crystalline 2D-CCOF films and developing stable device architectures.

Purpose of the Study:

• To synthesize a highly crystalline and conductive 2D-CCOF film.
• To construct stable 2D-CCOF-based spintronic devices and evaluate their performance.
• To investigate the role of graphene as a protective layer in device fabrication.

Main Methods:

• Synthesis of a high-crystallinity 2D-CCOF film.
• In situ magnetic conductive-probe atomic force microscopy (mCP-AFM) for characterization.
• Fabrication of half-spin valve devices using 2D-CCOF and graphene.

Main Results:

• Successful synthesis of a highly crystalline and conductive 2D-CCOF film.
• Demonstration of high chiral-induced spin selectivity (CISS) (>90% spin polarization at room temperature).
• Construction of stable graphene-protected 2D-CCOF spintronic devices exhibiting chirality-dependent magnetoresistance.

Conclusions:

• The developed 2D-CCOF exhibits excellent spin selectivity, paving the way for efficient spin control.
• Stable solid-state chiral spintronic devices can be realized using 2D-CCOFs with graphene interlayers.
• This work addresses critical challenges in 2D-CCOF film synthesis and device fabrication.