A tight-binding study of channel modulation in atomic-scale Si:P nanowires

It has been well understood that ultrathin, highly P δ-doped Si (Si:P) nanowires are metallic at charge-neutrality (Ref. [5]). This work extends the scope of tight-binding modeling beyond charge-neutrality to examine the channel modulation of a 1.5nm wide, 1/4 monolayer(ML)-doped Si:P nanowire and its effect on the channel conductance. Subband-anticrossing plays a key role in the channel modulation, creating a local minimum in the ballistic conductance as the channel is occupied with more electrons. While the channel modulation causes a fluctuation in the conductance, nanowires still remain metallic boding well for their utility as potential interconnects.