Signature of electronic correlations in the optical conductivity of the doped semiconductor Si:P
Signature of electronic correlations in the optical conductivity of the doped semiconductor Si:P
复制标题
掺杂半导体 Si:P 光导率的电子相关性特征
DOI：
10.1103/physrevb.75.205203
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发表时间：
2006
影响因子：
3.7
通讯作者：
H. Lohneysen
中科院分区：
文献类型：
--
作者：
M. Hering;M. Scheffler;M. Dressel;H. Lohneysen
Electronic transport in highly doped but still insulating silicon at low temperatures is dominated by hopping between localized states; it serves as a model system of a disordered solid for which the electronic interaction can be investigated. We have studied the frequency-dependent conductivity of phosphorus-doped silicon in the terahertz frequency range $(30\phantom{\rule{0.3em}{0ex}}\mathrm{GHz}\char21{}3\phantom{\rule{0.3em}{0ex}}\mathrm{THz})$ at low temperatures $T\ensuremath{\geqslant}1.8\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. The crossover in the optical conductivity from a linear to a quadratic frequency dependence as predicted by Efros and Shklovskii [Sov. Phys. JETP 54, 218 (1982)] is observed qualitatively; however, the simple model does not lead to a quantitative agreement. Covering a large range of donor concentration, our temperature- and frequency-dependent investigations reveal that electronic correlation effects between the localized states play an important and complex role at low temperatures. In particular, we find a superlinear frequency dependence of the conductivity that highlights the influence of the density of states, i.e., the Coulomb gap, on the optical conductivity. When approaching the metal-to-insulator transition by increasing doping concentration, the dielectric constant and the localization length exhibit critical behavior.
Electronic transport in highly doped but still insulating silicon at low temperatures is dominated by hopping between localized states; it serves as a model system of a disordered solid for which the electronic interaction can be investigated. We have studied the frequency-dependent conductivity of phosphorus-doped silicon in the terahertz frequency range $(30\phantom{\rule{0.3em}{0ex}}\mathrm{GHz}\char21{}3\phantom{\rule{0.3em}{0ex}}\mathrm{THz})$ at low temperatures $T\ensuremath{\geqslant}1.8\phantom{\rule{0.3em}{0ex}}\mathrm{K}$. The crossover in the optical conductivity from a linear to a quadratic frequency dependence as predicted by Efros and Shklovskii [Sov. Phys. JETP 54, 218 (1982)] is observed qualitatively; however, the simple model does not lead to a quantitative agreement. Covering a large range of donor concentration, our temperature- and frequency-dependent investigations reveal that electronic correlation effects between the localized states play an important and complex role at low temperatures. In particular, we find a superlinear frequency dependence of the conductivity that highlights the influence of the density of states, i.e., the Coulomb gap, on the optical conductivity. When approaching the metal-to-insulator transition by increasing doping concentration, the dielectric constant and the localization length exhibit critical behavior.