Thermal Decoherence and Disorder Effects on Chiral-Induced Spin Selectivity

Area of Science:

• Condensed Matter Physics
• Materials Science
• Organic Electronics

Background:

• Spin-dependent electron transport in helical organic molecules is crucial for spintronics.
• Existing coherent tunneling models fail to explain experimental length and temperature dependencies of spin polarization.

Purpose of the Study:

• To develop a theoretical model incorporating thermal and disorder effects on spin transport.
• To explain experimental observations of spin polarization in helical organic molecules.

Main Methods:

• Nonlinear master equation formalism applied to a tight-binding helical Hamiltonian.
• Inclusion of disordered onsite energies and temperature-dependent hopping probabilities.
• Analysis of spin-dependent conductance and polarization as a function of molecular length and temperature.

Main Results:

• The model successfully explains the observed length and temperature dependence of spin polarization.
• Spin polarization increases with molecular length at room temperature.
• Thermal excitation and disorder-induced Anderson localization interplay, affecting spin polarization.

Conclusions:

• Thermally activated hopping in disordered systems provides a mechanism for unexpected spin polarization behavior.
• The developed model offers a more comprehensive understanding of spin transport in helical organic molecules.