物理系学术报告       Physics Department Seminar

 

82615:30-16:3012-201

 

 

 

Charge fluctuations and Superconductivity in iron-pnictides LaOFeAs

 

Dr. Sen Zhou

Boston College and Rutgers Univeristy

 

 

  

 

We present a scenario for iron-pnictide superconductivity mediated by charge fluctuations that are strongly enhanced by Fe-As intersite electronic interactions. Deriving an eight-band extended Hubbard model including Fe 3d and As 4p orbitals for the LaOFeAs family, we show that charge fluctuations induced by p-d charge transfer and As orbital polarization interactions in the Fe-pnictogen structure peak at wavevectors (0, 0), and (p, 0) and (p, p) respectively. Intraorbital pairing attraction develops at these wavevectors and the solution of the linearized Eliashberg equation shows robust s-wave superconductivity with both s±  and s++ symmetry.