Effect of Rashba spin-orbit coupling interaction on energy states of silicon disk-shaped quantum dot

Silicon quantum dots (QDs) are considered an excellent platform for spin qubits due to their weak spin-orbit interaction (SOI). Indeed, due to quantum confinement, novel spin properties arise from the SOI. In this work, we have studied the influence of the Rashba SOI and the confinement potential on the energy spectrum of an electron confined in a Silicon disk-shaped quantum dot, in the presence of an external magnetic field. The effects of the QD size, the confinement potential and the Rashba alpha coefficient on the energy levels are also studied. We used the effective mass approximation to determine the energy levels and their wave functions for different states. The results are presented as a function of the magnetic field in the presence and absence of SOI. We find that the energy levels of the electrons behave very differently depending on the magnetic field. The energy of all states changes with increasing magnetic field and each energy level splits into two and the energy difference between these two levels also increases with magnetic field, in the presence and absence of SOI. The energy levels are proportional to the Rashba alpha coefficient and inversely proportional to the radius of the QD

Investigation of the electronic and thermoelectric properties of nitrogen chains doping SWCNT: ab initio study

In this work, we have investigated the electronic and thermoelectric properties of CN, C2N2 and C4N2 nanotubes resulting from doping of nitrogen atoms, three and two N-zigzag chains on small (3,3) single walled carbon nanotube (SWCNT) respectivelly. All calculations were performed via DFT theory using WIEN2K code. The electronic structure calculations were done using GGA with TB-mBJ exchange potential, while the thermoelectric calculations were done using semi-classical Boltzmann transport theory. The results show that all structures are energetically stable. The electronic behaviour of (3,3) SWCNT transforms from semiconductor to metal in CN nanotube and to topological Weyl semimetal (WSM) state for C2N2 and C4N2 nanotubes. The calculations of thermoelectric properties, including electrical conductivity, Seebeck coefficient and power factor, reaveal that the N-doping enhances the thermoelectric properties of pristine nanotube. SWCNT with nitrogen doping has promising electronic and thermoelectric capabilities that make it a potential for electronic and thermoelectric devices