We present a theoretical study of spin-orbit interaction effects on single wall carbon nanotubes and curved graphene nanoribbons by means of a realistic multiorbital tight-binding model, which takes into account the full symmetry of the honeycomb lattice.

Aug 1, 1997 · While the pseudopotential was build using the hopping parameter α0=2.569 eV in graphite [23], the best general agreement between our results and those provided by the two tight-binding models is achieved using as hopping parameter γ0 …

Here we keep Vppπ = 0, Vppσ = 1, λI = 0.2 and VAB = 0.8. (b) SH (red line) and OH (blue line) conductivities calculated as functions of energy. The grey line depicts the density of states (DOS...

Only nearest neighbor (NN) hoppings are considered, with Vppπ = 0 (this does not affect our conclusions, see the main text). Without specification, the spin-orbit coupling parameter ξ = 4.5 eV...

Download scientific diagram | (a) Band structure calculations along some symmetry lines in the 2D BZ for Vppπ = 0, Vppσ =1 eV, and λI = 0. The blue line represents the results for VAB = 0.0 ...

In the present research, we have used Vppπ = 2.5 eV [17]. Kx and Ky are the wave vectors of carbon nanotubes [17,18], and they are given by 3 3 3h3h2 3 ( + ) +

We analyze the effect of tensional strain in the electronic structure of graphene. In the absence of electron-electron interactions, within linear elasticity theory, and a tight-binding approach, we observe that strain can generate a bulk spectral gap.

FIG. 1. The Fourier image T (q, dGG) of the model for the electron hopping between two graphene layers: T (r + zez) = T (R) = Vppσ(R)(R · ez/R)2 + Vppπ(R)[1 − (R · ez/R)2] where R = ‖R‖ and Vppσ(R) = V 0ppσ exp[−(R − dGG)/R0], Vppπ(R) = V 0 ppπ exp[−(R − aCC)/R0].

分别往R方向和R的垂直方 向的投影来计算轨道的相 互作用。 两个与R垂直投影 的相互作用为Vppπ，而在R 方向上投影的相互作用为 Vppσ Rx Rz.

May 5, 2022 · 根据已经学到的量子力学的知识, 对于一个核外电子的波函数, 我们知道其可以为 ss , pp 轨道波函数, 在不考虑自旋的情况下则是由 n, l, mn,l,m 三个量子数来描述. 而真正的周期性势场 U(→r)U (r) 与 V(→r)V (r) 是有区别的. 所以我们将其差异部分, 也就是 U(→r) − V(→r − R m)U (r) −V (r − Rm) 视为微扰哈密顿量. 那么就有对波函数 ψ(→r)ψ(r) : [− ℏ 2 2m∇ 2 + U(→r)]ψ(→r) = Eψ(→r)[−2mℏ2 ∇2 + U (r)]ψ(r) = E ψ(r) 对于不同的格点, 有着不同的势场 V(→r − R m)V (r − …