On the Quadron State in Parabolic Quantum Dots

Abstract

In this work we consider a quadron – a state of four carriers – two electrons and two holes in quantum dots with parabolic confinement. By using the Hatree-Fock method, the binding energies of the quadron and biexciton have been calculated for a full range of the electron-to-hole oscillator length ratio. The effect of the magnetic field on the binding energy of the quadron and biexciton has been also investigated. The crossing between anti-binding and binding in both the excited quadron and biexciton states for the certain ranges of the electron-to-hole oscillator length ratio has been found.

Charged excitons or trions in 2D parabolic quantum dots?

“…We consider the system of electrons and holes in a 2D quantum dot with parabolic potential, and in a magnetic field B z. The total Hamiltonian of the system of N electrons and M holes (N = 2, M = 1 or N = 1, M = 2 for charged excitons and trions) can be written in the effective-mass approximation, as follows [13][14][15],…”

“…Quite recently, new terms "duo", "trio", "quatuor" for quasi-particle consisting of two, three and four charge carriers, respectively has been introduced in quantum dots by Combescot [12] and "quadron" for four charge carriers in 2D semiconductor quantum dots by us [13][14][15] to distinguish them from conventional excitons, charged excitons and biexcitons. In particular, self-organized semiconductor quantum dots are still in special interest of researchers today, since the binding energies of quasi-particles in the system are large and the effect of magnetic fields can be studied along with the symmetry of the quantum dot.…”

“…In particular, self-organized semiconductor quantum dots are still in special interest of researchers today, since the binding energies of quasi-particles in the system are large and the effect of magnetic fields can be studied along with the symmetry of the quantum dot. [12][13][14][15][16][17][18][19][20][21][22].…”

“…In [12][13][14][15] the authors have demonstrated the essential differences between ordinary biexciton and "quatuor" [12] or "quadron" [13][14][15] in quantum dots. The main reason for these differences is the confinement impact on the charged carriers in the quantum dot, where multi-particle pair interactions between four carriers should be considered equally.…”

“…The main reason for these differences is the confinement impact on the charged carriers in the quantum dot, where multi-particle pair interactions between four carriers should be considered equally. In our previous works [13][14][15] we have demonstrated that the confinement and the Coulomb interaction in a small InAs quantum dot lead to a bound quadron, rather a conventional biexciton.…”