The hubbard model and the metal-insulator phase transition at high temperatures

1975 ◽  
Vol 25 (9) ◽  
pp. 1077-1078
Author(s):  
E. Heiner
Keyword(s):  
Phase Transition ◽  
Hubbard Model ◽  
High Temperatures ◽  
Metal Insulator ◽  
Insulator Phase Transition

scholarly journals Direct detection of metal-insulator phase transitions using the modified Backus-Gilbert method

2018 ◽  
Vol 175 ◽  
pp. 03008 ◽  
Author(s):  
Maksim Ulybyshev ◽  
Christopher Winterowd ◽  
Savvas Zafeiropoulos
Keyword(s):  
Phase Transition ◽  
Hubbard Model ◽  
Order Parameter ◽  
Hexagonal Lattice ◽  
Monte Carlo Algorithm ◽  
Alternative Methods ◽  
Local Order ◽  
Metal Insulator ◽  
Local Order Parameter ◽  
Insulator Phase Transition

The detection of the (semi)metal-insulator phase transition can be extremely difficult if the local order parameter which characterizes the ordered phase is unknown. In some cases, it is even impossible to define a local order parameter: the most prominent example of such system is the spin liquid state. This state was proposed to exist in the Hubbard model on the hexagonal lattice in a region between the semimetal phase and the antiferromagnetic insulator phase. The existence of this phase has been the subject of a long debate. In order to detect these exotic phases we must use alternative methods to those used for more familiar examples of spontaneous symmetry breaking. We have modified the Backus-Gilbert method of analytic continuation which was previously used in the calculation of the pion quasiparticle mass in lattice QCD. The modification of the method consists of the introduction of the Tikhonov regularization scheme which was used to treat the ill-conditioned kernel. This modified Backus-Gilbert method is applied to the Euclidean propagators in momentum space calculated using the hybrid Monte Carlo algorithm. In this way, it is possible to reconstruct the full dispersion relation and to estimate the mass gap, which is a direct signal of the transition to the insulating state. We demonstrate the utility of this method in our calculations for the Hubbard model on the hexagonal lattice. We also apply the method to the metal-insulator phase transition in the Hubbard-Coulomb model on the square lattice.

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

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

Disappearance of the quasi-one-dimensional plasmon at the metal-insulator phase transition of indium atomic wires

2008 ◽  
Vol 77 (20) ◽  
Author(s):  
Canhua Liu ◽  
Takeshi Inaoka ◽  
Shin Yaginuma ◽  
Tomonobu Nakayama ◽  
Masakazu Aono ◽  
...  
Keyword(s):  
Phase Transition ◽  
Metal Insulator ◽  
One Dimensional ◽  
Atomic Wires ◽  
Insulator Phase Transition

scholarly journals Effect of Sintering Temperature on Metal-Insulator Phase Transition in La1-xCaxMnO3 Perovskites

2020 ◽  
Vol 2 (1) ◽  
pp. 37-42
Author(s):  
Arunachalam M ◽  
Thamilmaran P ◽  
Sakthipandi K
Keyword(s):  
Phase Transition ◽  
Bulk Modulus ◽  
Sintering Temperature ◽  
Magnetic Sensors ◽  
Temperature Dependent ◽  
Metal Insulator ◽  
Wide Range ◽  
Different Temperatures ◽  
Insulator Phase Transition

Lanthanum calcium based perovskites are found to be advantageous for the possible applications in magnetic sensors/reading heads, cathodes in solid oxide fuel cells, and frequency switching devices. In the present investigation La0.3Ca0.7MnO3 perovskites were synthesised through solid state reaction and sintered at four different temperatures such as 900, 1000, 1100 and 1200˚ C. X-ray powder diffraction pattern confirms that the prepared La0.3Ca0.7MnO3 perovskites have orthorhombic structure with Pnma space group. Ultrasonic in-situ measurements have been carried out on the La0.3Ca0.7MnO3 perovskites over wide range of temperature and elastic constants such as bulk modulus of the prepared La0.3Ca0.7MnO3 perovskites was obtained as function of temperature. The temperature-dependent bulk modulus has shown an interesting anomaly at the metal-insulator phase transition. The metal insulator transition temperature derived from temperature-dependent bulk modulus increases from temperature 352˚ C to 367˚ C with the increase of sintering temperature from 900 to 1200˚ C.

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