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Magnetic instability in strongly correlated superconductors
Bogdan A Bernevig1, Robert B Laughlin, David I Santiago
1Department of Physics, Stanford University, Stanford, California 94305, USA.
Physical Review Letters
|November 13, 2003
Summary
A new Gossamer Hamiltonian model reveals that superconducting cuprates become unstable with strong electron repulsion. Increasing this repulsion drives a quantum phase transition to an antiferromagnetic insulator state.
Area of Science:
- Condensed Matter Physics
- Materials Science
Background:
- Superconducting cuprates are complex materials exhibiting fascinating electronic properties.
- Understanding the interplay between superconductivity and electron correlation is crucial.
Purpose of the Study:
- To investigate the stability of superconducting cuprates using a novel phenomenological model.
- To explore the quantum phase transition driven by on-site Coulomb repulsion.
Main Methods:
- Utilizing the proposed Gossamer Hamiltonian framework.
- Analyzing the behavior of the system at half-filling with varying Coulomb repulsion.
Main Results:
- The Gossamer superconductor model demonstrates instability towards an antiferromagnetic insulator at half-filling.
- A quantum phase transition occurs as on-site Coulomb repulsion increases.
- Near the transition, superconducting and insulating states become spectroscopically indistinguishable.
Conclusions:
- The Gossamer Hamiltonian provides a valuable model for understanding electron correlation effects in cuprates.
- Strong on-site Coulomb repulsion fundamentally alters the electronic state from superconducting to antiferromagnetic insulating.