scholarly journals Three-dimensional electronic structures and the metal-insulator transition in Ruddlesden-Popper iridates

2016 ◽  
Vol 94 (11) ◽  
Author(s):  
A. Yamasaki ◽  
H. Fujiwara ◽  
S. Tachibana ◽  
D. Iwasaki ◽  
Y. Higashino ◽  
...  
Keyword(s):  
Electronic Structures ◽  
Three Dimensional ◽  
Insulator Transition ◽  
Metal Insulator Transition ◽  
Metal Insulator

Correlations Between Physical and Crystallographic Parameters in the (Bi, Pb)2Sr2 (Ca, Y)Cu2O8+δ Superconductors

1998 ◽  
Vol 12 (29n31) ◽  
pp. 3306-3312 ◽  
Author(s):  
Laurent Manifacier ◽  
Gaston Collin ◽  
Nicole Blanchard
Keyword(s):  
Hole Concentration ◽  
Three Dimensional ◽  
Covalent Bonding ◽  
Insulator Transition ◽  
Type Ii ◽  
Two Dimensional ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Internal Parameters ◽  
Hole Localization

Systematic studies of the lead and yttrium substituted Bi-2212 phase were performed on various compositions ranging between 0 and 0.8 for Pb and between 0 and 0.9 for Y. Crystallographic measurements reveal that the two modulations observed in unleaded and highly Pb-substituted samples are closely linked, the main differences being that the commensurate component disappears in type II (lead type) modulation, along with the modulation of the Bi 3+ ion. We argue that this is due to a covalent bonding between Bi-O planes. The study of internal parameters, including modulation amplitudes, of the Bi2Sr2 ( Ca 1-x, Y x) Cu2O 8+x/2+δ system reveals three distinct regimes with very different behaviors, corresponding to the overdoped, underdoped and insulating regimes. By comparing these results to the variation of the diamagnetic shielding with Y and Pb contents, we conclude that yttrium and lead affect more the mobility of the holes than the hole concentration itself. Y seems to induce, rather than a metal/insulator transition, a switch from a three-dimensional to a two-dimensional regime with a hole localization in the CuO 2 planes.

Enhancement of three-dimensional electron standing waves at the metal–insulator transition in 1T-TaS2

1999 ◽  
Vol 420 (2-3) ◽  
pp. 269-274 ◽  
Author(s):  
W. Yamaguchi ◽  
O. Shiino ◽  
T. Endo ◽  
T. Hasegawa ◽  
K. Kitazawa
Keyword(s):  
Three Dimensional ◽  
Standing Waves ◽  
Insulator Transition ◽  
Dimensional Electron ◽  
Metal Insulator Transition ◽  
Metal Insulator

scholarly journals Metal–Insulator Transition in Three-Dimensional Semiconductors

Symmetry ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1345
Author(s):  
Klaus Ziegler
Keyword(s):  
Symmetry Breaking ◽  
Spontaneous Symmetry Breaking ◽  
Critical Point ◽  
Order Parameter ◽  
Three Dimensional ◽  
Insulator Transition ◽  
Metal Insulator Transition ◽  
Metallic Behavior ◽  
Metal Insulator ◽  
Scattering Rate

We use a random gap model to describe a metal–insulator transition in three-dimensional semiconductors due to doping, and find a conventional phase transition, where the effective scattering rate is the order parameter. Spontaneous symmetry breaking results in metallic behavior, whereas the insulating regime is characterized by the absence of spontaneous symmetry breaking. The transition is continuous for the average conductivity with critical exponent equal to 1. Away from the critical point, the exponent is roughly 0.6, which may explain experimental observations of a crossover of the exponent from 1 to 0.5 by going away from the critical point.

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