TY - JOUR AU - Sobol, O. O. PY - 2018/10/23 Y2 - 2024/03/28 TI - Variational Method for the Calculation of Critical Distance Between Two Coulomb Centers in Graphene JF - Ukrainian Journal of Physics JA - Ukr. J. Phys. VL - 59 IS - 5 SE - Nanosystems DO - 10.15407/ujpe59.05.0531 UR - https://ujp.bitp.kiev.ua/index.php/ujp/article/view/2018479 SP - 531 AB - <p>The supercritical instability in a system of two identical charged impurities in gapped graphene described in the continuous limit by the two-dimensional Dirac equation has been studied. The case where the charge of each impurity is subcritical, but their sum exceeds the critical value calculated in the version with a single Coulomb center, is considered. Using the developed variational method, the dependence of the critical distance Rcr between the impurities on their total charge is calculated. The Rcr-value is found to grow as the total impurity charge increases and the quasiparticle band gap decreases. The results of calculations are compared with those obtained in earlier researches.</p> ER -