Non-orthogonal Theory of Polarons and Application to Pyramidal Quantum Dots

Details Non-orthogonal Theory of Polarons and Application to Pyramidal Quantum Dots Non-orthogonal Theory of Polarons and Application to Pyramidal Quantum Dots

2006-10-21

arxiv.org/abs/cond-mat/0610596v3

Phys. Rev. B 76, 035329 (2007)

Physics

Condensed Matter

Other Condensed Matter

17 pages, 11 figures, 3 tables

Scientific paper

10.1103/PhysRevB.76.035329

We present a general theory for semiconductor polarons in the framework of the Froehlich interaction between electrons and phonons. The latter is investigated using non-commuting phonon creation/annihilation operators associated with a natural set of non-orthogonal modes. This setting proves effective for mathematical simplification and physical interpretation and reveals a nested coupling structure of the Froehlich interaction. The theory is non-perturbative and well adapted for strong electron-phonon coupling, such as found in quantum dot (QD) structures. For those particular structures we introduce a minimal model that allows the computation and qualitative prediction of the spectrum and geometry of polarons. The model uses a generic non-orthogonal polaron basis, baptized the "natural basis". Accidental and symmetry-related electronic degeneracies are studied in detail and are shown to generate unentangled zero-shift polarons, which we consistently eliminate. As a practical example, these developments are applied to realistic pyramidal GaAs QDs. The energy spectrum and the 3D-geometry of polarons are computed and analyzed, and prove that realistic pyramidal QDs clearly fall in the regime of strong coupling. Further investigation reveals an unexpected substructure of "weakly coupled strong coupling regimes", a concept originating from overlap considerations. Using Bennett's entanglement measure, we finally propose a heuristic quantification of the coupling strength in QDs.

Affiliated with

Also associated with

No associations

Rating

Non-orthogonal Theory of Polarons and Application to Pyramidal Quantum Dots does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Non-orthogonal Theory of Polarons and Application to Pyramidal Quantum Dots, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Non-orthogonal Theory of Polarons and Application to Pyramidal Quantum Dots will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-552911