Effect of spin fluctuations on Tc from density-functional theory for superconductors

The transverse spin fluctuations are introduced to the density functional theory for superconductors (SCDFT). Paramagnons are treated within the random phase approximation and assumed to be the same for the normal and superconducting state. The effect of spin fluctuations on Tc is studied for a few simple metals at ambient pressure and niobium at several pressures up to 80 GPa.Comment: 11 pages, 2 tables, 2 figure

Effect of C-face 4H-SiC(0001) deposition on thermopower of single and multilayer graphene in AA, AB and ABC stacking

The Seebeck coefficient in multilayer graphene is investigated within the density-functional theory, using the semiclassical Boltzmann equations and interpolating the bands in a maximally-localized Wannier functions basis set. We compare various graphene stackings (AA, AB and ABC) both free-standing and deposited on a $4H$-SiC(0001) C-terminated substrate. We find that the presence of the SiC substrate can significantly affect the thermopower properties of graphene layers, depending on the stacking, providing a promising way to tailor efficient graphene-based devices.Comment: 7 pages, 4 figure