Peculiarities of the electron mechanism of superconductivity

Renormalization of Energy Structure and Oscillation Period in the de Haas–van Alphen Effect at the Strong Intersite Coulomb Interaction

“…As was noted previously, 4,5) when the hole concentration in a system described by the Hubbard model is low and U is large, the intersite Coulomb interaction plays an important role owing to its relatively weak screening. In this case, at distances close to interatomic distances, the order of magnitude of the characteristic energy V of the Coulomb interaction between electrons is comparable to that of U.…”

“…Due to the occurrence of holes in the system upon doping, the ion in the nearest neighborhood of the site where a hole is located necessarily acquires a different single-site energy [see x1 and eqs. (3)- (5)]. This means that at the finite number of holes at each moment of time, the single-site energy for N 1 lattice sites is " and that for the other N 2 ¼ N À N 1 lattice sites (N is the total number of sites) is " À V .…”

“…The manifestation of the intersite correlations in the physical properties of systems has been considered in many works (see, for instance, refs. [4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. However, until recently, no attention has been paid to the fact that a strong intersite correlation (SIC) can cause the splitting of the energy bands of the Fermi states into subbands.…”

The Kohn-Luttinger effect and anomalous pairing in new superconducting systems and graphene

“…It was concluded in [59] Historically, this model was formulated almost immediately after the origination of quantum mechan-ics and is a predecessor of some important models in condensed matter theory (in particular, the s − d(f )−model and the Hubbard model). The ShubinVonsovsky model was actively used in analyzing polaron states in solids [61] and the metal-insulator transition [62], as well as in studying the effect of the intersite Coulomb interaction on the superconducting properties of strongly correlated systems [63][64][65].…”

Coulomb repulsion of holes and competition between $${d_{{x^2} - {y^2}}}$$ d x 2 − y 2 -wave and s-wave parings in cuprate superconductors

“…The kinematic mechanism of Cooper instability was also of the electron origin and ensured high superconducting transition temperatures. The inclusion of the intersite Coulomb interaction between fermions in the ShubinVonsovsky model [6,7] leads to a decrease in the superconducting transition temperature [8][9][10] and gives temperatures matching the experimental data.…”