A first-principles study of phthalocyanine-based multifunctional spintronic molecular devices

Area of Science:

• Materials Science
• Condensed Matter Physics
• Nanotechnology

Background:

• Graphene nanoribbons (GNRs) exhibit unique spin-dependent electronic properties.
• Phthalocyanine (Pc) molecules are versatile organic semiconductors with potential in molecular electronics.

Purpose of the Study:

• To theoretically investigate the spin-dependent transport properties of Pc molecules interfaced with zigzag-edged GNRs (zGNRs).
• To explore the modulation of spin filtering and the emergence of magnetoresistance effects in transition metal phthalocyanine (TMPc) molecular junctions.

Main Methods:

• First-principles calculations were employed to simulate molecular junctions.
• Analysis of spin-resolved transmission spectra, molecular projected self-consistent Hamiltonian, and projected density of states.

Main Results:

• Perfect spin filtering was observed due to molecular symmetry and zGNR spin splitting.
• Spin filtering direction was inverted by altering the magnetic orientation of transition metal atoms (Mn, Cr) within the Pc molecule.
• Antiparallel magnetic configurations of zGNR electrodes induced bias-controlled conduction, leading to spin rectifying and giant magnetoresistance.

Conclusions:

• TMPc molecular junctions exhibit tunable spin filtering and magnetoresistance properties.
• The findings provide a theoretical basis for designing multifunctional spintronic devices utilizing TMPc molecules and GNRs.