Supercritical Coulomb center and excitonic instability in graphene

2009 ◽  
Vol 80 (16) ◽  
Author(s):  
O. V. Gamayun ◽  
E. V. Gorbar ◽  
V. P. Gusynin
Keyword(s):  
Coulomb Center

Symmetry Breaking Induced Activation of Nanocrystal Optical Transitions

MRS Advances ◽  
2018 ◽  
Vol 3 (14) ◽  
pp. 711-716 ◽  
Author(s):  
Peter C. Sercel ◽  
Andrew Shabaev ◽  
Alexander L. Efros
Keyword(s):  
Optical Properties ◽  
Fine Structure ◽  
Symmetry Breaking ◽  
Semiconductor Nanocrystals ◽  
Radiative Lifetime ◽  
Multipole Expansion ◽  
Cdse Nanocrystals ◽  
Coulomb Center ◽  
Charged Center ◽  
Positively Charged

ABSTRACTWe have analysed the effect of symmetry breaking on the optical properties of semiconductor nanocrystals due to doping by charged impurities. Using doped CdSe nanocrystals as an example, we show the effects of a Coulomb center on the exciton fine-structure and optical selection rules using symmetry theory and then quantify the effect of symmetry breaking on the exciton fine structure, modelling the charged center using a multipole expansion. The model shows that the presence of a Coulomb center breaks the nanocrystal symmetry and affects its optical properties through mixing and shifting of the hole spin and parity sublevels. This symmetry breaking, particularly for positively charged centers, shortens the radiative lifetime of CdSe nanocrystals even at room temperature, in qualitative agreement with the increase in PL efficiency observed in CdSe nanocrystals doped with positive Ag charge centers [A. Sahu et.al., Nano Lett. 12, 2587, (2012)]. The effect of the charged center on the photoluminescence and the absorption spectra is shown, with and without the presence of compensating charges on the nanocrystal surface. While spectra of individual nanocrystals are expected to shift and broaden with the introduction of a charged center, configuration averaging and inhomogeneous broadening are shown to wash out these effects. The presence of compensating charges at the NC surface also serves to stabilize the band edge transition energies relative to NCs with no charge centers.

Asymptotic theory of the strongly asymmetric two-Coulomb-center problem

1985 ◽  
Vol 32 (6) ◽  
pp. 3425-3434 ◽  
Author(s):  
T. P. Grozdanov ◽  
R. K. Janev ◽  
V. Yu. Lazur
Keyword(s):  
Asymptotic Theory ◽  
Center Problem ◽  
Coulomb Center

Asymptotic behaviour terms relativistic two - coulomb - center problem in approximate of united atom

1999 ◽  
Vol 4 (0) ◽  
pp. 145-150
Author(s):  
А. В. Катернога ◽  
В. Ю. Лазур ◽  
С. І. Мигалина
Keyword(s):  
Asymptotic Behaviour ◽  
Center Problem ◽  
Coulomb Center

scholarly journals Asymptotic properties of the three-Coulomb-center problemeZ1ZZ

2006 ◽  
Vol 73 (3) ◽  
Author(s):  
V. Yu. Lazur ◽  
M. V. Khoma ◽  
R. K. Janev
Keyword(s):  
Asymptotic Properties ◽  
Coulomb Center

Scattering of electrons by a Coulomb center

1980 ◽  
Vol 23 (4) ◽  
pp. 281-284 ◽  
Author(s):  
N. V. Samsonenko ◽  
S. L. Dubkov
Keyword(s):  
Coulomb Center

scholarly journals Generalized quantum mechanical two-Coulomb-center problem (Demkov problem)

2013 ◽  
Vol 22 (9) ◽  
pp. 090306 ◽  
Author(s):  
A. M. Puchkov ◽  
A. V. Kozedub ◽  
E. O. Bodnia
Keyword(s):  
Quantum Mechanical ◽  
Center Problem ◽  
Coulomb Center
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