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Hole Transport in the Upper Hubbard Band in Cu‐Doped Germanium under Uniaxial Pressure
Author(s) -
Walukiewicz W.,
Dubon O.D.,
Silvestri H.H.,
Silvestri H.H.,
Haller E.E.,
Haller E.E.
Publication year - 1998
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/(sici)1521-3951(199812)210:2<253::aid-pssb253>3.0.co;2-0
Subject(s) - condensed matter physics , delocalized electron , doping , electrical resistivity and conductivity , scattering , materials science , germanium , hubbard model , metal–insulator transition , valence (chemistry) , ground state , electron mobility , metal , chemistry , physics , atomic physics , superconductivity , optics , organic chemistry , quantum mechanics , silicon , metallurgy
The ground state of substitutional Cu in Ge undergoes a transformation from a highly localized 1s 3 to a much more extended 1s 2 2s 1 configuration at the uniaxial pressure of 0.42 GPa along the [100] direction. The transformation is associated with a dramatic reduction of the resistivity. The observed metal–insulator transition is explained with the formation of extended Hubbard bands well separated from the valence band. It is shown that the hole mobility in the upper Hubbard band is limited by scattering from ionized and neutral Cu centers in the delocalized 1s 2 2s 1 configuration. The concentration of the scattering centers and thus also the hole mobility can be controlled by uniaxial pressure. Hole mobilities as high as 10 7 cm 2 /Vs have been observed at 16 K for intermediate uniaxial stresses. These results indicate a very weak coupling between acoustic phonons and the holes in the upper Hubbard band.