Localization phase diagram for the energetically and substitutionally disordered Anderson/quantum percolation model

1988 ◽  
Vol 89 (5) ◽  
pp. 3279-3284 ◽  
Author(s):  
L. J. Root ◽  
J. L. Skinner
Keyword(s):  
Phase Diagram ◽  
Percolation Model ◽  
Quantum Percolation

scholarly journals EFFECT OF FIELD DIRECTION AND FIELD INTENSITY ON DIRECTED SPIRAL PERCOLATION

2006 ◽  
Vol 17 (09) ◽  
pp. 1285-1302 ◽  
Author(s):  
SANTANU SINHA ◽  
S. B. SANTRA
Keyword(s):  
Phase Diagram ◽  
Critical Behavior ◽  
Disordered Systems ◽  
Universality Class ◽  
Two Dimensions ◽  
Percolation Model ◽  
Field Direction ◽  
Critical Properties ◽  
External Bias ◽  
Directional Field

Directed spiral percolation (DSP) is a new percolation model with crossed external bias fields. Since percolation is a model of disorder, the effect of external bias fields on the properties of disordered systems can be studied numerically using DSP. In DSP, the bias fields are an in-plane directional field (E) and a field of rotational nature (B) applied perpendicular to the plane of the lattice. The critical properties of DSP clusters are studied here varying the direction of E field and intensities of both E and B fields in two-dimensions. The system shows interesting and unusual critical behavior at the percolation threshold. Not only the DSP model is found to belong in a new universality class compared to that of other percolation models but also the universality class remains invariant under the variation of E field direction. Varying the intensities of the E and B fields, a crossover from DSP to other percolation models has been studied. A phase diagram of the percolation models is obtained as a function of intensities of the bias fields E and B.

QUANTUM PERCOLATION

1995 ◽  
Vol 09 (23) ◽  
pp. 2989-3024 ◽  
Author(s):  
ABHIJIT MOOKERJEE ◽  
INDRA DASGUPTA ◽  
TANUSRI SAHA
Keyword(s):  
Low Temperatures ◽  
Two Dimensions ◽  
Percolation Model ◽  
Quantum Percolation ◽  
Resonant States

In this review we describe and analyze various numerical attempts at understanding transport in the Quantum Percolation Model. We conclude that in two-dimensions all states are localized, though not necessarily exponentially localized, and that transport at low temperatures is dominated by probabilistically exceptional necklace-like resonant states.

QUANTUM PERCOLATION AND CHARGE TRANSPORT IN HIGH Tc SUPERCONDUCTORS

2000 ◽  
Vol 14 (25n27) ◽  
pp. 3012-3019
Author(s):  
V. DALLACASA ◽  
P. DI SIA
Keyword(s):  
Charge Transport ◽  
Transport Properties ◽  
Interpolation Formula ◽  
Percolation Model ◽  
High Tc Superconductors ◽  
Metal Insulator ◽  
High Tc ◽  
Coulomb Gap ◽  
Quantum Percolation ◽  
Localised States

We have investigated the consequences of internal fields on transport properties in insulators close to a metal-insulator-superconductor transition. An interpolation formula for the resistivity as a function of temperature describing insulating, metallic and superconducting regimes has been deduced in the framework of a quantum percolation model in which hopping processes on localised states occur. The contribution to the internal fields on carriers has been taken into account up to quadrupole terms. The resistivity follows a law ρ ∪(T0)δ T e(T0/T)1/2 where T0 corresponds to a coulomb gap and exhibits anisotropic quadrupole angular dependence, suggesting a correlation with the pseudo-gap observed in superconductors in the underdoped regime.

scholarly journals Field-induced quantum breakdown of superconductivity in magnesium diboride

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Soon-Gil Jung ◽  
Jung Min Lee ◽  
Tae-Ho Park ◽  
Tian Le ◽  
Xin Lu ◽  
...  
Keyword(s):  
Magnesium Diboride ◽  
Ion Irradiation ◽  
Percolation Model ◽  
Quantum Phase ◽  
Resistive State ◽  
Iron Ion ◽  
Electron Pairs ◽  
Practical Applications ◽  
Quantum Percolation ◽  
Different Thickness

AbstractThe quantum breakdown of superconductivity (QBS) is the reverse, comprehensive approach to the appearance of superconductivity. A quantum phase transition from superconducting to insulating states tuned by using nonthermal parameters is of fundamental importance to understanding the superconducting (SC) phase but also to practical applications of SC materials. However, the mechanism of the transition to a nonzero resistive state deep in the SC state is still under debate. Here, we report a systematic study of MgB2 bilayers with different thickness ratios for undamaged and damaged layers fabricated by low-energy iron-ion irradiation. The field-induced QBS is discovered at a critical field of 3.2 Tesla (=Hc), where the quantum percolation model best explains the scaling of the magnetoresistance near Hc. As the thickness of the undamaged layer is increased, strikingly, superconductivity is recovered from the insulating state associated with the QBS, showing that destruction of quantum phase coherence among Cooper electron pairs is the origin of the QBS.

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