Schematic illustration of the considered armchair GNR structures with the number of carbon chains between two edges: (a) graphitic and (b) normal-conducting leads. The latter ones are modeled by square lattices. A magnetic gated insulator is deposited to create a spin-dependent potential barrier in the center of device.
(a) Oscillation of conductance vs the barrier height in the GGG structures with different widths: (semiconducting, dashed) and 23 (metallic, solid line). (b) illustrates the transmission coefficient calculated from Eq. (10) for different modes . Other parameters are , , and .
(a) Spin polarization as a function of the barrier height for the same structures as in Fig. 2(a). (b) shows an example of the effects of the different ribbon widths on the spin polarization: (dashed), 27 (dashed-dotted), and 33 (solid line). Everywhere , , and .
Comparison of conductance (a) and LDOS (b) in different structures: graphitic (dashed) and normal-conducting (solid lines, ) leads. Everywhere , , , , and .
[(a) and (b)] Comparison of spin polarization in the different structures: graphitic (dashed) and normal-conducting (solid lines, ) leads. [(c) and (d)] The spin polarization in the latter one with different coupling strengths: (dashed), (dashed-dotted), and (solid lines). The ribbon widths are [(a) and (c)] and 23 [(b) and (d)]. Other parameters are , , , and .
(a) LDOS illustrating the existence of confined states in the device and (b) conductance in the NGN junctions as a function of the Fermi energy for different device lengths: (solid) and 102 nm (dashed lines). (c) shows the dependence of energy spacing of confined states on the inverse of device length. Everywhere , , , and .
(a) Conductance and (b) spin polarization in the NGN structures as functions of the barrier height for different device lengths: 68 nm (solid), 74 nm (dashed), and 79 nm (dashed-dotted lines). The oscillation of vs the device length for different values of (c) [630 meV (solid), 655 meV (dashed-dotted), and 681 meV (dashed line)] and of (d) [250 meV (dashed-dotted), 300 meV (solid), and 350 meV (dashed line)]. Other parameters are , , [in (a)–(c)], , [in (d)] and .
Article metrics loading...
Full text loading...