Metal-Insulator Transition in a Generalized Hubbard Model with   Correlated Hopping at Half-Filling
  In the present paper metal-insulator transition is studied in a generalized Hubbard model with correlated hopping at half-filling and zero temperature. Single-particle Green function and energy spectrum of electron system are calculated. The expressions for energy gap width and the concentration of polar states (holes or doublons) are obtained. The conditions for metallic and insulating states are found. 
Leonid Didukh and Vasyl Hankevych (Ternopil State Technical   University, Ukraine)