Reduction of exciton mass by uniaxial stress in GaAs/AlGaAs quantum wells

Abstract

Abstractauthoren We show experimentally that the uniaxial stress applied along the twofold symmetry axis of a high‐quality heterostructure containing a wide GaAs/AlGaAs quantum well leads to considerable modification of the exciton‐polariton reflectivity spectra. We observe: (i) the energy splitting of the light‐hole and heavy‐hole exciton resonances to appear and (ii) the increase of the quasiperiod (divergence) of spectral oscillations related to the optically allowed exciton‐polariton transitions. A theoretical analysis shows that the first effect is due to the strain‐induced reduction of crystal symmetry. The divergence of spectral oscillations is found to be due to the strain‐induced decrease of the heavy‐hole exciton mass. The effective mass is reduced by 5% at the pressure of P=0.23GPa. This effect shows the potentiality of spectroscopic ways of strain detection in semiconductors.

Optical activity of quantum wells

“…We have fitted both the spectral and incidence-angle dependencies of the Stokes parameters P circ and Plin by Eqs. ( 9), (10). Figure 2 demonstrates that the developed theory describes all four dependencies very well.…”

“…While metamaterials convert light polarization due to a special design of building blocks, semiconductor nanostructures are birefringent as-grown. The polarization conversion has been demonstrated in a number of experiments on quantum wells (QWs) [7][8][9][10][11] and quantum dots [12,13]. The low symmetry of QWs can be caused by in-plane deformations [8][9][10] or by microscopic structure of interfaces [14,15], while the birefringence of self-assembled quantum dots appears due to their anisotropic shape [13].…”

Exciton-polariton interference controlled by electric field

“…In Refs. [22,23], an effect of a uniaxial strain on the exciton states is experimentally and theoretically studied for wide quantum wells (QWs). A nontrivial effect of the phase inversion of the spectral oscillations has been predicted.…”

Зависимость Светоэкситонного Взаимодействия От Ширины Квантовой Ямы Во Внешнем Однородном Электрическом Поле

“…Внешние воздействия приводят к новым эффектам, которые можно наблюдать с помощью оптической спектроскопии. Например, поле одноосного сжатия, приложенное к широкой КЯ, индуцирует эффект сближения масс экситонов тяжелой и легкой дырок и приводит к инверсии фазы спектральных осцилляций экситонных особенностей в оптических спектрах [14,15]. Магнитное поле, в зависимости от ориентации относительно оси квантования, приводит либо к эффективному увеличению массы экситона, либо к зависимости g-фактора экситона от волнового вектора его движения [16][17][18][19][20][21][22][23][24].…”