scholarly journals Localization length and impurity dielectric susceptibility in the critical regime of the metal-insulator transition in homogeneously dopedp-typeGe

2000 ◽  
Vol 62 (4) ◽  
pp. R2255-R2258 ◽  
Author(s):  
Michio Watanabe ◽  
Kohei M. Itoh ◽  
Youiti Ootuka ◽  
Eugene E. Haller
Keyword(s):  
Localization Length ◽  
Insulator Transition ◽  
Critical Regime ◽  
Dielectric Susceptibility ◽  
Metal Insulator Transition ◽  
Metal Insulator

Hopping Conduction Near the Metal-Insulator Transition in CdMnTe:In and Evidence for a Magnetic Hard Gap in the Density of States

1994 ◽  
Vol 08 (07) ◽  
pp. 905-912 ◽  
Author(s):  
I. Terry ◽  
T. Penney ◽  
S. von Molnár ◽  
P. Becla
Keyword(s):  
Carrier Concentration ◽  
Density Of States ◽  
Low Temperatures ◽  
Localization Length ◽  
Insulator Transition ◽  
Variable Range Hopping ◽  
Coulomb Interactions ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Magnetic Polarons

A series of resistivity curves is obtained as a function carrier concentration in just one sample of the dilute magnetic persistent photoconductor Cd0.91Mn0.09Te:In. The measurements, made at carrier concentrations approaching the metal-insulator transition, reveal a cross-over from an exp(To/T)1/2 dependence to an exp(EH/T) form when lowering temperature. The exp(To/T)1/2 dependence is characteristic of variable range hopping in the presence of Coulomb interactions, while the energy EH in the activated form is associated with a hard gap in the density of states that is magnetic in origin. All the data are shown to scale onto a single curve. The localization length. ξ, is found to have the same critical dependence on carrier concentration as that of the measured dielectric constant, κ, when approaching the metal-insulator transition. The temperature dependence of the resistivity is interpreted in terms of the orientation of Mn spins by carriers due to the s-d exchange interaction (the formation of magnetic polarons). This model can also account for the large positive and negative magnetoresistance observed in Cd0.91Mn0.09Te:In at low temperatures.

METAL–INSULATOR TRANSITION AND THE TEMPERATURE OF THE PSEUDOGAP ANOMALY OPENING IN PRASEODYMIUM DOPED Y1-zPrzBa2Cu3O7-δ SINGLE CRYSTALS

2013 ◽  
Vol 27 (04) ◽  
pp. 1350029 ◽  
Author(s):  
R. V. VOVK ◽  
Z. F. NAZYROV ◽  
I. L. GOULATIS ◽  
A. CHRONEOS ◽  
V. M. PINTO SIMOES
Keyword(s):  
Electrical Resistivity ◽  
Single Crystals ◽  
Insulator Transition ◽  
Critical Regime ◽  
Significant Shift ◽  
Asymptotic Dependence ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
The One ◽  
Praseodymium Doping

The influence of praseodymium doping on the electrical resistivity in the ab-plane of Y 1-z Pr z Ba 2 Cu 3 O 7-δ single crystals, is investigated. It is determined that as the concentration of praseodymium (0.0 ≤ z ≤ 0.5) is rising there occurs a significant shift of the temperature regions, corresponding to the metal–insulator transitions, as well as to the regime of the implementation of the pseudogap anomaly. The part of the curves related to the metal–insulator transition are well described by means of an asymptotic dependence that corresponds to the implementation of a quantum critical regime in the system, the so-called law of the "one third".

Hopping conduction in p-type MoS2 near the critical regime of the metal-insulator transition

2015 ◽  
Vol 107 (22) ◽  
pp. 223107 ◽  
Author(s):  
Tae-Eon Park ◽  
Joonki Suh ◽  
Dongjea Seo ◽  
Joonsuk Park ◽  
Der-Yuh Lin ◽  
...  
Keyword(s):  
Insulator Transition ◽  
Critical Regime ◽  
Hopping Conduction ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
P Type

The Influence of Local Magnetization on Transport in Cd0.91Mn0.09Te:In

1992 ◽  
Vol 290 ◽  
Author(s):  
S. Von Molnar ◽  
T. Penney ◽  
I. Terry ◽  
P. Becla
Keyword(s):  
Transport Properties ◽  
Carrier Concentration ◽  
Magnetic Semiconductors ◽  
Localization Length ◽  
Insulator Transition ◽  
Local Magnetization ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Magnetic Polarons ◽  
Transport Effect

AbstractWe describe the influence of local magnetization on electron localization and transport properties on the insulating side of the metal insulator transition in the dilute magnetic persistent photoconductor Cd0.091 Mn0.09Te:ln. Measurements of both the temperature dependence of the transport properties, and also the dielectric constant, are reported for just one sample in which the carrier concentration n was varied by photodoping. From these results we are able to extract the carrier concentration dependence of the localization length and the permitivity of the electrons. We also report onl a new transport effect which occurs at ultra low temperatures and/or carrier concentrations very close to the metal insulator transition. We find that this mechanism is totally magnetic in origin and are able to explain it in terms of the well devewloped ideas of magnetic polarons in magnetic semiconductors.

Spin Polarized Tunneling at the Metal-Insulator Transition

2003 ◽  
Vol 17 (18n20) ◽  
pp. 3723-3725 ◽  
Author(s):  
W. Teizer ◽  
F. Hellman ◽  
R. C. Dynes
Keyword(s):  
Spin Polarization ◽  
Density Of States ◽  
Insulator Transition ◽  
Critical Regime ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Spin Polarized ◽  
Quantum Critical ◽  
Spin Polarized Tunneling

We have determined the spin polarized density of states (DOS) of 3-d amorphous Gd x Si 1-x in the quantum critical regime of a tunable Metal-Insulator Transition (MIT). Using a spin polarized BCS DOS we fit the data and extract the spin polarization P.

Transport in polyaniline near the critical regime of the metal-insulator transition

1993 ◽  
Vol 48 (24) ◽  
pp. 17685-17694 ◽  
Author(s):  
Reghu Menon ◽  
C. O. Yoon ◽  
D. Moses ◽  
A. J. Heeger ◽  
Y. Cao
Keyword(s):  
Insulator Transition ◽  
Critical Regime ◽  
Metal Insulator Transition ◽  
Metal Insulator
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