Self-trapping Of Acoustic Polaron In Semiconductor Quantum Dots

Electron mobility is an important physical parameter, for which isThe bound between micro electron movement and macro current-voltfeatures. Electron mobility varies markedly when the electron statechange from free to self-trapped. Many physics properties ofphotoelectric material are related to the electron state. The shortrange interactions between the electrons and the phonons can beregarded as the trigger electronic trap. Therefore, It first need to getHamiltonian electron interaction with longitudinal phonon as well asissues related to research on the Acoustic Polaron self-trapping.First the Hamiltonian of electron-phonon interaction in QD havebeen exported. Found the Hamiltonian is similar with Xiao’ s results,This have checked that this method which we take is correct.Then the self-traps of Acoustic Polaron in QD have been discussed.Use the method of electron and phonon through deformation potentialcoupling to derive the QD Hamiltonian electron and longitudinalphonon interaction. Then use variational method to calculate theground-state energy. Found the results are similar with Hou’ which isnot consistent with the general law of Acoustic Polaron self-trapping.That is, with decreasing scale of QD, it close to the lower dimension, Acoustic Polaron self-traps more easily.The products of αck0Approximately a constant. when the radius of theQD is0.07and0.15, The products of αck0are close to0.6and2.6.Which can be inferred that the coupling constant is equal with the2D case when R is0.07, and when the radius of the quantum dot is0.15, the Electron-phonon strength has been reduced to zero becauseof the structure characteristics.It is more easier to measurement of carrier mobility, and it isgenerally known that the carrier mobility is corresponding to theeffective mass. Calculating effective mass, even using migration rateto count the traps of electron is an effective method. In this paper, amethod of approximation and LLP methods were used to calculatedcharacteristics of the effective mass of the acoustic polaron inquantum dot. It was found that there is a big difference between thetwo methods, But the transform point of the effective mass isapproximate consistent. Then we compared the results with theground state energy, It is found that the transformation point of theground state energy is closely consistent with that of the effectivemass. That verified the existence of self-trapping in polaron ofquantum dot, the method what we take has been successfully used indealing with the issue of the effective mass.