An ultradense 2D electron system can be realized by adsorbing PH3 precursor molecules onto an atomically clean Si surface, followed by epitaxial Si overgrowth. By controlling the PH3 coverage the carrier density of such system can easily reach ∼1014 cm−2, exceeding that typically found in GaAs/AlGaAs structures by more than two-three orders of magnitude. We report on a first systematic characterization of such novel system by means of standard magnetotransport. The main findings include logarithmic temperature dependence of zero-field conductivity and logarithmic negative magnetoresistance. We analyzed the results in terms of scaling theory of localization in two dimensions.
@article{arxiv.cond-mat/0305482,
title = {Weak Localization in an Ultradense 2D Electron Gas in $\delta$-doped Silicon},
author = {M. A. Zudov and C. L. Yang and R. R. Du and T. -C. Shen and J. -Y. Ji and J. S. Kline and J. R. Tucker},
journal= {arXiv preprint arXiv:cond-mat/0305482},
year = {2007}
}