Showing papers on "Mott transition published in 1974"
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01 Jan 1974
TL;DR: In this article, a discussion is given of some aspects of the metal insulator transition and the status of the "minimum metallic conductivity" is discussed, and the concept is valid for liquids and in some, but not all, solid systems.
Abstract: A discussion is given of some aspects of the metal insulator transition. Particular attention is paid to the status of the “minimum metallic conductivity”. The concept is valid for liquids, and in some, but not all, solid systems.
2,109 citations
TL;DR: In this article, it was shown that the intra-atomic interaction in cerium is considerably smaller than seems to have been believed in the past, and it is argued that in metallic cerium, U is only of the order of a few electron volts.
Abstract: The α-γ transition in cerium is considered as a Mott transition. From spectroscopic data it is concluded that the intra-atomic interaction, U, is considerably smaller than seems to have been believed in the past. Here it is argued that in metallic cerium, U is only of the order of a few electron volts. Current band calculations of the width of a 4f band state are presumably very unreliable, and correlation effects on the ionic crystal potential are probably of considerable importance. Still, some conventional band calculations seem to imply a width of nearly one electron volt for densities appropriate for the dense a phase in cerium. Several experimental facts on the properties of γ and α cerium lead us to assert that metallic cerium cannot promote its f electron into the (sd) configuration. This is most clearly seen from its cohesive energy properties, and it is shown that if cerium were to attain an (sd)4 configuration, say in the a or a phase, this would lead to a totally unacceptable behaviou...
353 citations
TL;DR: Spin echo spectra, Knight shift and spin-lattice relaxation time are measured on 31 P in silicon crystals with phosphorus concentrations ranging from 4.5×10 18 cm -3 to 9.6×10 19 cm −3.
Abstract: Spin echo spectra, Knight shift and spin-lattice relaxation time are measured on 31 P in silicon crystals with phosphorus concentrations ranging from 4.5×10 18 cm -3 to 9.6×10 19 cm -3 over a temperature region from 4.2 K to 0.4 K. The shift and width of 31 P line is atrributed to the inhomogeneous electron contact field. The results together with those of 29 Si (J. Phys. Soc. Japan 36 (1974) 1377) support the Mott transition mechanism of metal-non metal transition and allow to interpret various properties of the metallic samples in terms of an electron gas with correlation.
24 citations
TL;DR: In this paper, the electronic structure of an impurity band in a heavily-doped semiconductor, in the metallic regime just above the Mott transition, is studied in a tight-binding scheme using a cumulant expansion.
Abstract: The electronic structure of an impurity band in a heavily-doped semiconductor, in the metallic regime just above the Mott transition, is studied in a tight-binding scheme using a cumulant expansion. The density of states shows no erosion in its centre near the impurity level; a result confirmed by a detailed comparison between results obtained either by a numerical simulation technique or by other analytical approaches. This comparison also shows that within a single-site framework, very different results can be obtained at the extremities of the spectrum whereas converging results are obtained at its centre. Possible extensions to cases where short-range order effects are important, such as in liquid-metal systems, are also discussed.
16 citations
TL;DR: In this article, the temperature dependence of the conductivity of ferromagnetic semiconductors was investigated for both the non-degenerate and degenerate case with allowance of the exchange interaction between moveable electrons and localized magnetic moments.
Abstract: The temperature dependence of the conductivity of ferromagnetic semiconductors is theoretically investigated for both the non-degenerate and degenerate case with allowance of the exchange interaction between moveable electrons and localized magnetic moments. For the former the temperaturedependence of the charge carrier density is found.
[Russian Text Ignored].
15 citations
01 Jan 1974
TL;DR: In this paper, the conductivity of compensated GaAs with Nd≈Na≈ ≈ 2.101 7 cm-3 was investigated down to T = 0,5°K.
Abstract: The conductivity of compensated GaAs with Nd≈Na≈ ≈2.5.101 7 cm-3 was investigated down to T = 0,5°K. To explain the results of the measurements it was suggested that the electrons at low temperature are localized in a narrow continuum of states near the bottom of the conduction band. At the appropriate concentration of the electrons a Mott transition occurs.
1 citations
01 Jan 1974
TL;DR: In this article, the SFRS linewidths were observed in n-CdS by observing the spin resonance and a new effect was described where simultaneous irradiation of the spins with laser light at frequency ωL and microwaves at frequency ε near the resonance results in forward scattering at ω L ±ωO which is more than three orders of magnitude greater than spontaneous SFRS.
Abstract: Electron delocalization is studied in n-CdS by observing the SFRS linewidths. A new effect is also described wherein simultaneous irradiation of the spins with laser light at frequency ωL and microwaves at frequency ωO near the spin resonance results in forward scattering at ωL ±ωO which is more than three orders of magnitude greater than spontaneous SFRS.