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.

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

Features of the Crystal Structure of Tm1–xYbxB12 Dodecaborides near a Quantum Critical Point and at a Metal–Insulator Transition

JETP Letters ◽  
2018 ◽  
Vol 108 (10) ◽  
pp. 691-696 ◽  
Author(s):  
N. E. Sluchanko ◽  
A. P. Dudka ◽  
O. N. Khrykina ◽  
N. B. Bolotina ◽  
A. N. Azarevich ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Critical Point ◽  
Quantum Critical Point ◽  
Insulator Transition ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Quantum Critical

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.

Symmetry breaking in the metal-insulator transition ofBaVS3

2002 ◽  
Vol 66 (7) ◽  
Author(s):  
T. Inami ◽  
K. Ohwada ◽  
H. Kimura ◽  
M. Watanabe ◽  
Y. Noda ◽  
...  
Keyword(s):  
Symmetry Breaking ◽  
Insulator Transition ◽  
Metal Insulator Transition ◽  
Metal Insulator

In Situ X-Ray Diffraction and XAFS Studies of Expanded Fluid Selenium Using Synchrotron Radiation

MRS Bulletin ◽  
1999 ◽  
Vol 24 (1) ◽  
pp. 26-31 ◽  
Author(s):  
K. Tamura ◽  
M. Inui
Keyword(s):  
Critical Point ◽  
Liquid Metals ◽  
Saturated Vapor ◽  
Insulator Transition ◽  
Pressure Curve ◽  
Expansion Process ◽  
Liquid Form ◽  
Metal Insulator Transition ◽  
Metal Insulator ◽  
Temperature And Pressure

A substantial and continuous volume expansion from liquid to rarefied vapor occurs by the change of temperature and pressure surrounding the liquid-vapor critical point without crossing the saturated vapor pressure curve. Many investigations have been carried out with molecular fluids including supercritical fluids, and several variations of the equation of state have been advanced since the famous work by van der Waals. In the expansion process the mean interatomic distance increases by up to 10 times that found under standard conditions. However reconstitution of the molecular units or other major structure changes are rare in these fluids. On the other hand, in the expansion process of metallic or semiconducting liquids, physical properties can drastically change. Liquid Hg, well-known as a prototype of liquid metals, undergoes a metal-insulator transition when the density is reduced to about 9 g/cm3 near the critical point.Elemental Se, which units in its liquid form is a semiconductor with a twofold-coordinated chain structure in which atoms are covalently bonded, also experiences a semiconductor-metal-insulator transition around the critical point (critical temperature and pressure data of Se: Tc = 1615°C, Pc = 385 bar, pc = 1.85 g/cm3).The first indication of the semiconductormetal (SC-M) transition in fluid Se was found in electrical conductivity data by Hoshino and co-workers. Figure 1 shows the contours of constant dc conductivity plotted on the pressure-temperature (P-T) plane. The high-conductivity region appears in the immediate vicinity of the critical point. Another indication of the SC-M transition was obtained from the measurement of the optical reflectivity by Seyer et al. Drude-like energy dependence of the reflectivity spectra was observed at elevated pressures and temperatures.

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