In the present work the possibility of simultaneous localization of two electrons in Δ100 and Δ001 valleys in ordered structures with Ge/Si(001) quantum dots (QD) was verified experimentally by the electron spin resonance (ESR) method. The ESR spectra obtained for the ordered ten-layered QD structure in the dark show the signal corresponding to electron localization in Si at the Ge QD base edges in Δ100, Δ010 valleys (gzz=1.9985, gin−plane=1.999). Light illumination causes the appearance of a new ESR line (gzz=1.999) attributed to electrons in the Δ001 valley localized at QD apexes. The observed effect is explained by enhancement of electron confinement near the QD apex by Coloumb attraction to the photogenerated hole trapped in a Ge QD.
@article{arxiv.1501.06757,
title = {Simultaneous Localization of Electrons in different $\Delta$-valleys in Ge/Si Quantum Dot Structures},
author = {Aigul Zinovieva and Natalia Stepina and Anatoly Dvurechenskii and Leonid Kulik and Gregor Mussler and Juergen Moers and Detlev Gruetzmacher},
journal= {arXiv preprint arXiv:1501.06757},
year = {2015}
}