Theoretical investigation of electronic and thermoelectric properties of single-wall carbon nanotube p–n junction

Electronic transport in an armchair Single-Wall Carbon Nanotube (SWCNT) p–n junction with axial magnetic flux was investigated via Landauer–Büttiker formalism and the nonequilibrium Greenʼs function technique. The electrical conductance G and Seebeck coefficient S were studied under different parameters, such as magnetic flux, on-site energy, circumference of SWCNT and Anderson disorder. The numerical calculation results demonstrate that in the absence of magnetic flux ϕ, quantized G plateaus can be obtained because there is no back scattering. The Seebeck coefficient S   is zero because electron population is balanced at both sides of Fermi level εFεF. For ϕ≠0ϕ≠0, an energy gap appears in the band structure of SWCNT. Nearly quantized G plateaus can still be obtained in the n–n region, while the G is small in the p–n region. In addition, the Seebeck coefficient S   shows an peak and a valley obviously at the edges of energy gap when electron population changes abruptly in the vicinity of εFεF. Whatʼs more, the Anderson disorder does not change G and S much because there are not edge states in SWCNT and the electron–hole mixture cannot be facilitated.

► The electrical conductance and the Seebeck coefficient properties of SWCNT based p–n junction with the axial magnetic flux are studied.
► For no magnetic flux, perfect tunneling happens since there is no back scattering.
► For nonzero magnetic flux, the Seebeck coefficient shows valley and peak structure at the edges of the energy gap.
► Disorder does not affect the electrical and thermoelectric properties of SWCNT p–n junction much.