Bond dissociation and correlation effects in molecular electronic devices.

Area of Science:

• Molecular electronics
• Quantum chemistry
• Condensed matter physics

Background:

• Understanding conductance changes in molecular junctions is crucial for molecular electronics.
• Electron-electron interactions significantly influence molecular properties and transport.

Purpose of the Study:

• To model the change in conductance of a diatomic molecule during bond breaking.
• To investigate the impact of electron-electron interactions on molecular conductance.
• To analyze the effect of spin-polarized contacts on molecular states.

Main Methods:

• A simplified model using the Hubbard Hamiltonian for electron interaction within the molecule.
• Neglecting electron interaction in the contacts.
• Analyzing electron transmission through the molecule.

Main Results:

• Strong electron repulsion significantly suppresses electron transmission upon bond breaking.
• Spin-polarized contacts couple molecular singlet and triplet states.
• The energy gap between the lowest molecular resonances is reduced due to spin-polarized contacts.

Conclusions:

• Electron-electron interactions play a critical role in determining molecular conductance, especially during bond dissociation.
• Spin-polarized contacts can modify the electronic structure of molecules, affecting charge transport.
• The model provides insights into the fundamental processes governing conductance in molecular electronic devices.