Charge order and superconductivity in low-dimensional organic conductors

Area of Science:

• Condensed Matter Physics
• Materials Science
• Theoretical Chemistry

Background:

• The interplay between spin density waves (SDW) and charge density waves (CDW) is crucial for understanding electronic properties in low-dimensional materials.
• Organic conductors exhibit complex electronic phases due to electron-electron interactions and specific band structures.

Purpose of the Study:

• To investigate the conditions under which spin density wave (SDW) and charge density wave (CDW) states coexist in a one-dimensional extended Hubbard model.
• To identify electron-filling parameters that stabilize this coexistent state, particularly in the context of organic conductors.
• To explore the relationship between these coexistent phases and the potential for superconductivity.

Main Methods:

• Utilizing a one-dimensional extended Hubbard model to simulate electronic behavior.
• Analyzing ground state energies and critical temperatures across various electron-filling scenarios.
• Investigating the influence of band parameters characteristic of organic conductors.

Main Results:

• The coexistent state of spin density wave (SDW) and charge density wave (CDW) is found to be stabilized under specific band parameters relevant to organic conductors.
• Ground state energies exhibit distinct cusp-like minima at electron fillings of the form n/4m, where n and m are integers.
• Critical temperatures for the coexistent state are predicted to show maxima at these n/4m-fillings, observable via X-ray scattering.

Conclusions:

• The study confirms the stabilization of the SDW-CDW coexistent state in one-dimensional models applicable to organic conductors.
• Specific electron fillings (n/4m) are identified as key for stabilizing this phase and potentially observing enhanced critical temperatures.
• The findings suggest a link between strong antiferromagnetic fluctuations and superconductivity at these particular fillings.