Ab initio investigation of boron nanodevices: conductances of the different geometric conformations

Conductances of different geometric conformations of boron ribbon devices are calculated by the \textit{ab} \textit{initio} method. The $I$--$V$ characteristics of three devices are rather different due to the difference in structure. The current of the hexagonal boron device is the largest and increases nonlinearly. The current of the hybrid hexagon-triangle boron device displays a large low-bias current and saturates at a value of about 5.2~$\mu $A. The current of the flat triangular boron flake exhibits a voltage gap at low bias and rises sharply with increasing voltage. The flat triangular boron device can be either conducting or insulating, depending on the field.