Program

P.63 -- Poster, NCTP-41

Date: Wednesday, 3 August 2016

Time: 08h30 - 10h00

Effects of phonons in the excitonic insulator in the 2D extended Falicov-Kimball model

Do Thi Hong Hai (1, 2) and Phan Van Nham (3)

(1) Department of Physics, Hanoi University of Mining and Geology, Duc Thang, Bac Tu Liem, Hanoi; (2) Faculty of Physics, Graduate University of Science and Technology, Hoang Quoc Viet, Cau Giay, Hanoi; (3) Institute of Research and Development, Duy Tan University, K7/25 Quang Trung, Danang.

Excitonic insulator instability in the 2D extended Falicov-Kimball model at zero temperature has been investigated when a coupling of electrons and vibrational degrees of freedom is taken into account. Adopting the unrestricted Hartree-Fock approximation, both electron-phonon interaction and electron-electron interaction are treated in an equal footing. Numerical results show us that the excitonic insulator coexists with the lattice displacement only if the electron-phonon coupling is large enough. At a given small electron-phonon coupling, one finds a stability of excitonic insulator only in between two critical points of the electron-electron interaction strength. Detail ground state phase diagrams of the excitonic-insulator in the model then are presented and discussed.

Presenter: Do Thi Hong Hai