Phase Diagram of the Two-Orbital Model for Iron-Based HTSC: Variational Cluster Approximation

JETP Letters ◽  
2019 ◽  
Vol 109 (1) ◽  
pp. 45-50 ◽  
Author(s):  
Ya. V. Zhumagulov ◽  
V. A. Kashurnikov ◽  
A. V. Krasavin ◽  
A. E. Lukyanov ◽  
V. D. Neverov
Keyword(s):  
Phase Diagram ◽  
Cluster Approximation ◽  
Iron Based ◽  
Variational Cluster Approximation

scholarly journals Vortex pinning and magnetic phase diagram of EuRbFe4As4 iron-based superconductor

2020 ◽  
Vol 33 (8) ◽  
pp. 084009 ◽  
Author(s):  
Vladimir Vlasenko ◽  
Kirill Pervakov ◽  
Sergey Gavrilkin
Keyword(s):  
Phase Diagram ◽  
Magnetic Phase ◽  
Magnetic Phase Diagram ◽  
Vortex Pinning ◽  
Iron Based

scholarly journals A study of the magnetic properties in the Hubbard model on the honeycomb lattice by variational cluster approximation

2016 ◽  
Vol 30 (23) ◽  
pp. 1650158 ◽  
Author(s):  
Atsushi Yamada
Keyword(s):  
Magnetic Properties ◽  
Hubbard Model ◽  
Quantum Monte Carlo ◽  
Large Scale ◽  
Interaction Strength ◽  
Honeycomb Lattice ◽  
Metallic State ◽  
Cluster Approximation ◽  
Nonmagnetic Metal ◽  
Variational Cluster Approximation

Magnetic properties of the half-filled Hubbard model on the honeycomb lattice, which is a simple model of graphene, are studied using the variational cluster approximation (VCA). We found that the critical interaction strength of a magnetic transition is slightly lower than that of the nonmagnetic metal-to-insulator transition and the magnetic order parameter is already nonnegligible at the latter transition point. Thus, a semi-metallic state becomes a magnetic insulator as the interaction strength increases, and a spin liquid state characterized by a Mott insulator without spontaneously broken spatial or spin symmetry, or a state very close to that is not realized in this system. Both the magnetic and nonmagnetic metal-to-insulator transitions are of the second-order. Our results agree with recent large scale quantum Monte Carlo (QMC) simulations.

scholarly journals Pressure-induced reconstitution of Fermi surfaces and spin fluctuations in S-substituted FeSe

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
T. Kuwayama ◽  
K. Matsuura ◽  
J. Gouchi ◽  
Y. Yamakawa ◽  
Y. Mizukami ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Density Of States ◽  
Spin Fluctuations ◽  
Fermi Surfaces ◽  
Lifshitz Transition ◽  
Different Types ◽  
Iron Based ◽  
Nuclear Magnetic

AbstractFeSe is a unique high-$$T_c$$ T c iron-based superconductor in which nematicity, superconductivity, and magnetism are entangled with each other in the P-T phase diagram. We performed $$^{77}$$ 77 Se-nuclear magnetic resonance measurements under pressures of up to 3.9 GPa on 12% S-substituted FeSe, in which the complex overlap between the nematicity and magnetism are resolved. A pressure-induced Lifshitz transition was observed at 1.0 GPa as an anomaly of the density of states and as double superconducting (SC) domes accompanied by different types of antiferromagnetic (AF) fluctuations. The low-$$T_{\mathrm{c}}$$ T c SC dome below 1 GPa is accompanied by strong AF fluctuations, whereas the high-$$T_{\mathrm{c}}$$ T c SC dome develops above 1 GPa, where AF fluctuations are fairly weak. These results suggest the importance of the $$d_{xy}$$ d xy orbital and its intra-orbital coupling for the high-$$T_{\mathrm{c}}$$ T c superconductivity.

scholarly journals Universal V-shaped temperature-pressure phase diagram in the iron-based superconductorsKFe2As2,RbFe2As2, andCsFe2As2

2015 ◽  
Vol 91 (5) ◽  
Author(s):  
F. F. Tafti ◽  
A. Ouellet ◽  
A. Juneau-Fecteau ◽  
S. Faucher ◽  
M. Lapointe-Major ◽  
...  
Keyword(s):  
Phase Diagram ◽  
Iron Based ◽  
Pressure Phase
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