Two-order parameters theory of the metal-insulator phase transition kinetics in the magnetic field

2018 ◽  
Vol 536 ◽  
pp. 469-473
Author(s):  
L.B. Dubovskii
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Order Parameters ◽  
Metal Insulator ◽  
Insulator Phase Transition ◽  
Phase Transition Kinetics ◽  
The Magnetic Field

scholarly journals Magnetic field driven metal-insulator phase transition in planar systems

2002 ◽  
Vol 66 (4) ◽  
Author(s):  
E. V. Gorbar ◽  
V. P. Gusynin ◽  
V. A. Miransky ◽  
I. A. Shovkovy
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Metal Insulator ◽  
Insulator Phase Transition ◽  
Planar Systems

DYNAMICS AND LOCAL STRUCTURE OF COLOSSAL MAGNETORESISTANCE MANGANITES

2000 ◽  
Vol 14 (25n27) ◽  
pp. 2725-2730 ◽  
Author(s):  
C. CASTELLANO ◽  
F. CORDERO ◽  
R. CANTELLI ◽  
C. MENEGHINI ◽  
S. MOBILIO ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Phase Transition ◽  
Wide Temperature Range ◽  
Colossal Magnetoresistance ◽  
Insulator Transition ◽  
Metal Insulator Transition ◽  
Double Peak ◽  
Metal Insulator ◽  
Temperature Range ◽  
The Magnetic Field

We report Extended X-ray Absorption Fine Structure and anelastic spectroscopy measurements on hole doped manganese oxides La 1-x Ca x MnO 3 which present the colossal magnetoresistance effect. EXAFS measurements were realized both in the absence and presence of an applied magnetic field of 1.1 Tesla, in a wide temperature range (between 330 and 77 K) and at various dopings (x = 0.25 and x = 0.33). The magnetic field orders the magnetic moments so favouring the electron mobility and the reduction of Mn-O octahedra distortions. We observe the presence of four short and two long Mn-O distances (1.93 and 2.05Å respectively) above and also below the metal-insulator phase transition. The overall distortion decreases but does not completely disappear in the metallic phase suggesting the possible coexistence of metallic and insulating regions at low temperatures. The magnetic field reduces the lattice distortions showing evidence of a microscopic counterpart of the macroscopic colossal magnetoresistance. We also present preliminary anelastic relaxation spectra in a wide temperature range from 900 K to 1 K on a sample with x = 0.40, in order to study the structural phase transitions and the lattice dynamics. A double peak has been observed at the metal-insulator transition in the imaginary part of Young's modulus. This double peak indicates that the metal-insulator transition could be a more complex phenomenon than a simple second order phase transition. In particular the peak at lower temperatures can be connected with the possible presence of inhomogeneous phase structures. Another intense dissipation peak has been observed corresponding to the structural orthorhombic-trigonal transition around 750 K.

The character of metal-insulator phase transition in V2O3 from the plasmon behaviour

1983 ◽  
Vol 48 (5) ◽  
pp. 471-474 ◽  
Author(s):  
S Stizza ◽  
I Davoli ◽  
R Bernardini ◽  
A Bianconi ◽  
M Benfatto
Keyword(s):  
Phase Transition ◽  
Metal Insulator ◽  
Insulator Phase Transition

First-principles study on the heterostructure of twisted graphene/hexagonal boron nitride/graphene sandwich structure

2021 ◽  
Author(s):  
Yiheng Chen ◽  
Wen-Ti Guo ◽  
Zi-si Chen ◽  
Suyun Wang ◽  
Jian-Min Zhang
Keyword(s):  
Phase Transition ◽  
Boron Nitride ◽  
Charge Density ◽  
First Principles ◽  
Sandwich Structure ◽  
Hexagonal Boron Nitride ◽  
Mulliken Population ◽  
Metal Insulator ◽  
Insulator Phase Transition ◽  
Twisted Graphene

Abstract In recent years, the discovery of "magic angle" graphene has given new inspiration to the formation of heterojunctions. Similarly, the use of hexagonal boron nitride, known as white graphene, as a substrate for graphene devices has more aroused great interest in the graphene/hexagonal boron nitride (G/hBN) heterostructure system. Based on the first principles method of density functional theory, the band structure, density of states, Mulliken population, and differential charge density of a tightly packed model of twisted graphene/hexagonal boron nitride/graphene (G/hBN/G) sandwich structure have been studied. Through the establishment of heterostructure models TBG inserting hBN with different twisted angles, it was found that the band gap, Mulliken population, and charge density, exhibited specific evolution regulars with the rotation angle of the upper graphene, showing novel electronic properties and realizing metal-insulator phase transition. We find that the particular value of the twist angle at which the metal-insulator phase transition occurs and propose a rotational regulation mechanism with angular periodicity. Our results have guiding significance for the practical application of heterojunction electronic devices.

The metal-insulator phase transition in the strained GdBiTe3

2013 ◽  
Vol 113 (17) ◽  
pp. 17A934 ◽  
Author(s):  
Tran Van Quang ◽  
Miyoung Kim
Keyword(s):  
Phase Transition ◽  
Metal Insulator ◽  
Insulator Phase Transition
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