Speaker
Mr
Denis Boyda
(Far Eastern Federal University)
Description
There was a long time disagreement in literature between theoretical calculations and experimental data about conductor-insulator phase transition in graphene. This contradiction was resolved in the papers [Phys. Rev. Lett. 111, 56801 (2013)] and [Phys. Rev. B 89, 195429 (2014)] where chiral condensate was studied taking into account screening of Coulomb potential by $\sigma$-electrons of carbon atoms. Unfortunately there was no explicit evidence that conductivity drops down simultaneously with appearance of chiral condensate. Therefore it is required to perform direct calculations of graphene conductivity in tight-binding model.
We performed Monte-Carlo simulations of graphene tight-biding model with realistic electron-electron interaction and calculated the dependence of conductivity on dielectric permittivity of substrate.
According to our calculations suspended graphene has conductivity $\sigma = 0.325\pm0.003 e2/\hbar$ which is very close to experimental value $\sigma = (1.01 \pm 0.04)e^2/4\hbar$. The phase transition in
conductivity is also shifted to unphysical region epsilon<1 due to
influence of $\sigma$-electrons.
Primary author
Mr
Denis Boyda
(Far Eastern Federal University)
Co-authors
Dr
Maksim Ulybyshev
(Regensburg University)
Dr
Victor Braguta
(Institute of Theoretical and Experimental Physics)
