2014/12/31 by Edyta N. Osika, E. N. Osika, B. Szafran
Materials Science · Physics and Astronomy · #Atomic orbital #Atomic physics #Condensed matter physics #Degenerate energy levels #Electron #Graphene research and applications #Ground state #Physics #Quantum and electron transport phenomena #Quantum mechanics #Topological Materials and Phenomena #Valence (chemistry) #cond-mat.mes-hall
paper · pdf · doi:10.1103/physrevb.91.085312
published as Physical Review B 91, 085312 (2015)
arxiv created 2015/02/09 · openalex publication_date 2015/02/27 · arxiv updated 2015/03/06 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
We consider electron states in n\text\ensuremath-p double quantum dots defined in a semiconducting carbon nanotube (CNT) by an external potential. We describe formation of extended single-electron orbitals originating from the conduction and valence bands confined in a minimum and a maximum of the external potential, respectively. We solve the problem of a confined electron pair using an exact diagonalization method within the tight-binding approach, which allows for a straightforward treatment of the conduction- and valence-band states, keeping an exact account for the intervalley scattering mediated by the atomic defects and the electron-electron interaction. The exchange interaction, which in the unipolar double dots is nearly independent of the axial magnetic field (B) and forms singletlike and tripletlike states, in the n\text\ensuremath-p system appears only for selected states and narrow intervals of B. In particular, the ground-state energy level of a n\text\ensuremath-p double dot is not split by the exchange interaction and remains fourfold degenerate at zero magnetic field also for a strong tunnel coupling between the dots.