Ballistic transport properties across nonuniform strain barriers in graphene

We study the effect of uniaxial strain on the transmission and the conductivity across a strain-induced barrier in graphene. At variance with conventional studies, which consider sharp barriers, we consider a more realistic, smooth barrier, characterized by a nonuniform, continuous strain profile. Our results are instrumental towards a better understanding of the transport properties in corrugated graphene.Comment: High Press. Res., to appea

Обобщенная модель транспорта электронов и тепла Ландауэра-Датты-Лундстрома в микро- и наноэлектронике

Generalized model of electron transport in the linear response regime developed by R. Landauer, S. Datta, and M. Lundstrom with application to the resistors of any dimension, any size and arbitrary dispersion working in ballistic, quasi-ballistic or diffusion regime up to calculation of conductivity near 0º K and at higher temperatures is summarized. There is also discussed still widely used concept of mobility, as well as the dissipation of heat and the voltage drop in the ballistic resistors.Излагается обобщенная модель транспорта электронов, развитая Р. Ландауэром, С. Даттой и М. Лундстромом,  вплоть до вычисления проводимости резисторов любой размерности, любого масштаба и произвольной дисперсии, работающих в баллистическом, квази-баллистическом или диффузионном режиме линейного отклика как вблизи 0º K, так и при высоких температурах. Обсуждаются и поныне широко используемое понятие подвижности, а также диссипация тепла и падение напряжения в баллистических резисторах

Учет рассеяния в транспортной модели Ландауэра-Датты-Лундстрома

Scattering of carriers in the LDL transport model during the changes of the scattering times in the collision processes is considered qualitatively. The basic relationship between the transmission coefficient T and the average mean free path  is derived for 1D conductor. As an example, the experimental data for Si MOSFET are analyzed with the use of various models of reliability.Качественно рассматривается рассеяние носителей тока и тепла в транспортной модели ЛДЛ по ходу изменения времен рассеяния в процессе столкновений. На примере 1D проводника выводится базовое соотношение между коэффициентом прохождения Т и средней длиной свободного пробега . В качестве примера анализируются экспериментальные данные для Si MOSFET с привлечением моделей различной достоверности.

The effect of spin polarization on the electron transport of molecular wires with diradical character

Some of the most promising materials for application in molecular electronics and spintronics are based on diradical chains. Herein, the proposed relation between increasing conductance with length and diradical character is revisited using ab initio methods that account for the static electron correlation effects. Electron transmission was previously obtained from restricted single determinant wavefuntions or tight-binding approximations, which are unable to account for static correlation. Broken Symmetry Unrestricted Kohn-Sham Density Functional Theory (BS-UKS-DFT) in combination with electron transport analysis based on electron deformation orbitals (EDOs) reflects an exponential decay of the electrical conductance with length. Also, other important effects such as quantum interference are correctly accounted for, leading to a decrease of the conductance as the diradical character increases. As a proof-of-concept, the electrical conductance obtained from BS-UKS-DFT and CASSCF(2,2) wavefunctions were compared in diradical graphene strips in the frame of the pseudo-π approach, obtaining very similar resultsXunta de Galicia | Ref. GRC2019/2