Electronic and Vibrational Properties of Adsorbed and Embedded Graphene and Bigraphene with Defects

Effect of step-edge on spectral properties and planar stability of metallic bigraphene

“…In [12], a perfect agreement of this result with ab initio calculations [30,31] is demonstrated. Interestingly, the same result was derived [14,28] within a trivial lattice dynamics approach (red curve 4) notwithstanding the perfect crystal structure consideration which inevitably sharpers the resonances in spectral densities. The role of the number of phonon states at ( ) E E K = is also proved by observations [12] and relevant calculations [14,28] of the transition temperature T c decrease with weakening of intercalation effect on the phonon DOS of graphite near ( ), E K e.g., T c = 11.5 К for CaC 6 , compared to 6.5 К for YbC 6 .…”

“…2(a) -green (3) and wine (2) dependences, respectively). This minimum resembles the Dirac V-singularity in electron density of grahene and similarly is responsible imperfection induced quasilocal states with frequencies close to ( ) K ω [14,28]. Note, that namely the polarized normal to graphene layers (quasiflexural) vibrations [29] should play a crucial role in, say, the Cooper pairing at superconducting transition.…”

Effects of symmetry breaking in low dimensional materials

“…This permits the expectations that modifications of the present Lifshitz model, as in Ref. [212] for single impurity at a gapless spectrum, or using the Anderson hybrid model [221] as in Ref. [228] (provided all the technical aspects be assured), will not essentially change the physical behavior of the system.…”

“…k , and with no restrictions in all the quasimomentum sums for the products of NR interaction matrices Â(0) j,n = T (0) j (2N ) −1 k Ĝ(0) k e ik•n (that are only present in their even combinations Â(0) j,n Â(0) j,−n ). The best-known effect of local perturbations consists in emergence of localized energy levels within the band gap, and those were already indicated for impurities in bilayer graphene [211,212]. As known from general theory [92,132], such levels are most pronounced at sufficiently low concentration of impurities (so that their indirect interactions can be neglected) when they are given by the poles of T matrices.…”

“…However, the most reliable structure for external tuning and rather simple for theoretical study is seen in the Bernal-stacked bilayer graphene, hence chosen here as the basic host system for studying impurity effects. Having introduced impurities in such a system, such as dopants in common semiconductor systems [34,210], there is a possibility for localized impurity levels to appear within the host spectrum gap [211,212]. Next, it is known that, at high enough impurity concentration, an intensive interaction between the localized impurity states related to these levels can take place.…”