Evidence for many-electron composite charge excitations in a Coulomb glass

Massey, J. G.; Lee, Mark

doi:10.1103/physrevb.62.r13270

“…This concept was confirmed by tunneling experiments 13,14 which reveal a parabolic dependence of the conductance measuring the DOS. The typical size of the Coulomb gap in doped semiconductors is 1 meV.…”

Section: B Coulomb Glassmentioning

confidence: 64%

Signature of electronic correlations in the optical conductivity of the doped semiconductor Si:P

Hering

¹

,

Scheffler

²

,

Dressel

³

et al. 2007

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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 GHz-3 THz͒ at low temperatures T ജ 1.8 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 ͑1982͔͒ 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.

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“…At low temperatures, Mott's T --1/4 relation valid for bulk material changes over into a T --1/2 relation when Coulomb interactions of electrons have to be taken into account [31][32][33][34]. Our data set is taken at temperatures well above this range so that Coulombic interactions are not observed.…”

Section: Variable Range Hoppingmentioning

confidence: 99%

Resistivity of Ultrathin (0.6-3.7 nm) IrSi Films on Si(100)

Grünleitner

¹

,

Semmelroth

²

,

Schulz

³

2001

phys. stat. sol. (a)

2

0

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Subject classification: 73.30.+y; 73.50.Dn; 73.61.Jc; S1.61 Ultrathin (0.6-3.7 nm) IrSi films are fabricated by electron beam evaporation of iridium metal onto n-type silicon (100) substrates and subsequent silicide formation at 500 C. The sheet resistivity is measured at various temperatures in the range from 15 to 300 K. The polycrystalline c-IrSi films which form for a film thickness in excess of 8 nm show a metal-like behaviour of the resistivity. Ultrathin IrSi films of thickness less than 4 nm show an anomalous resistivity that increases with decreasing temperature. The exponential law observed for the resistivity is found to be consistent with hopping transport in amorphous IrSi predicted by the structure analysis for the thin films.

show abstract

“…At low temperatures, Mott's T --1/4 relation valid for bulk material changes over into a T --1/2 relation when Coulomb interactions of electrons have to be taken into account [31][32][33][34]. Our data set is taken at temperatures well above this range so that Coulombic interactions are not observed.…”

Section: Variable Range Hoppingmentioning

confidence: 99%

Resistivity of Ultrathin (0.6–3.7 nm) IrSi Films on Si(100)

Grünleitner

¹

,

Semmelroth

²

,

Schulz

³

2001

phys. stat. sol. (a)

0

View full text Add to dashboard Cite

Subject classification: 73.30.+y; 73.50.Dn; 73.61.Jc; S1.61 Ultrathin (0.6-3.7 nm) IrSi films are fabricated by electron beam evaporation of iridium metal onto n-type silicon (100) substrates and subsequent silicide formation at 500 C. The sheet resistivity is measured at various temperatures in the range from 15 to 300 K. The polycrystalline c-IrSi films which form for a film thickness in excess of 8 nm show a metal-like behaviour of the resistivity. Ultrathin IrSi films of thickness less than 4 nm show an anomalous resistivity that increases with decreasing temperature. The exponential law observed for the resistivity is found to be consistent with hopping transport in amorphous IrSi predicted by the structure analysis for the thin films.

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Evidence for many-electron composite charge excitations in a Coulomb glass

Cited by 24 publications

References 19 publications

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

Resistivity of Ultrathin (0.6-3.7 nm) IrSi Films on Si(100)

Resistivity of Ultrathin (0.6–3.7 nm) IrSi Films on Si(100)

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