Ferromagnetism in the two-dimensional Hubbard model with long-range hopping

Open Physics ◽  
2013 ◽  
Vol 11 (1) ◽  
Author(s):  
Pavol Farkašovský ◽  
Hana Čenčariková
Keyword(s):  
Hubbard Model ◽  
Long Range ◽  
Quantum Monte Carlo ◽  
Ferromagnetic State ◽  
Critical Value ◽  
Exact Diagonalization ◽  
Two Dimensional ◽  
Wide Range ◽  
Quantum Monte Carlo Method ◽  
Generalized Type

AbstractThe combination of small-cluster exact-diagonalization calculations and the quantum Monte Carlo method is used to examine ferromagnetism in the two-dimensional Hubbard model with a generalized type of hopping. It is found that the long-range hopping with exponentially decaying hopping amplitudes t ij ∼ − q Ri−Rj stabilizes the ferromagnetic state for a wide range of electron interactions U and electron concentrations n > 1. The critical value of the hopping parameter q c above which the ferromagnetic state becomes stable is calculated numerically and the ground-state phase diagram of the model is discussed for physically the most interesting cases.

scholarly journals The Influence of Long-Range Hopping on Ferromagnetism in the Hubbard Model

1998 ◽  
Vol 12 (07n08) ◽  
pp. 803-808 ◽  
Author(s):  
Pavol Farkašovský
Keyword(s):  
Magnetic Field ◽  
Phase Diagram ◽  
External Magnetic Field ◽  
Hubbard Model ◽  
Long Range ◽  
General Expression ◽  
Ferromagnetic State ◽  
Critical Value ◽  
Exact Diagonalization ◽  
Matrix Elements

The phase diagram of the Hubbard model in an external magnetic field is examined by extrapolation of small-cluster exact-diagonalization calculations. Using a general expression for the hopping matrix elements (tij ~ q|i-j|) the influence of long-range hopping (band asymmetry) on ferromagnetism in this model is studied. It is found that the long-range hopping (nonzero q) stabilizes ferromagnetism in an external magnetic field for n > 1. In the opposite limit n≤1 the fully polarized ferromagnetic state is generally suppressed with increasing q. The critical value of magnetic field h below which the ferromagnetic state becomes unstable is calculated numerically.

scholarly journals Itinerant ferromagnetism in narrow-band metals

2021 ◽  
Vol 24 (4) ◽  
pp. 42701
Author(s):  
P. Farkašovský
Keyword(s):  
Hubbard Model ◽  
Long Range ◽  
Quantum Monte Carlo ◽  
Narrow Band ◽  
Lattice Structure ◽  
Ferromagnetic State ◽  
Charge Density Waves ◽  
Research Activity ◽  
Itinerant Ferromagnetism ◽  
Cooperative Phenomena

Since its introduction in 1963, the Hubbard model has becomes one of the most popular models used in the literature to study cooperative phenomena in narrow-band metals (ferromagnetism, metal-insulator transitions, charge-density waves, high-Tc superconductivity). Amongst all these cooperative phenomena, the problem of itinerant ferromagnetism in the Hubbard model has the longest history. However, in spite of an impressive research activity in the past, the underlying physics (microscopic mechanisms) that leads to the stabilization of itinerant ferromagnetism in Hubbard model (narrow-band metals) is still far from being understood. In this review we present our numerical results concerning this subject, which have been reached by small cluster exact diagonalization, density matrix renormalization group and quantum Monte Carlo calculations within various extensions of the Hubbard model. Particular attention is paid to a description of crucial mechanisms (interactions) that support the stabilization of the ferromagnetic state, and namely: (i) the long-range hopping, (ii) the correlated hopping, (iii) the long-range Coulomb interaction, (iv) the flat bands and (v) the lattice structure. Most of the presented results have been obtained for the one-dimensional case, but the influence of the increasing dimension of the system on the ferromagnetic state is also intensively discussed.

scholarly journals Phase separation in the two-dimensional Hubbard model: A fixed-node quantum Monte Carlo study

1998 ◽  
Vol 58 (22) ◽  
pp. R14685-R14688 ◽  
Author(s):  
A. C. Cosentini ◽  
M. Capone ◽  
L. Guidoni ◽  
G. B. Bachelet
Keyword(s):  
Monte Carlo ◽  
Phase Separation ◽  
Hubbard Model ◽  
Quantum Monte Carlo ◽  
Monte Carlo Study ◽  
Two Dimensional ◽  
Fixed Node

scholarly journals Striped phases in the two-dimensional Hubbard model with long-range Coulomb interaction

1998 ◽  
Vol 58 (20) ◽  
pp. 13506-13509 ◽  
Author(s):  
G. Seibold ◽  
C. Castellani ◽  
C. Di Castro ◽  
M. Grilli
Keyword(s):  
Hubbard Model ◽  
Long Range ◽  
Coulomb Interaction ◽  
Two Dimensional ◽  
Striped Phases

scholarly journals Strange metallicity in the doped Hubbard model

Science ◽  
2019 ◽  
Vol 366 (6468) ◽  
pp. 987-990 ◽  
Author(s):  
Edwin W. Huang ◽  
Ryan Sheppard ◽  
Brian Moritz ◽  
Thomas P. Devereaux
Keyword(s):  
Hubbard Model ◽  
Quantum Monte Carlo ◽  
High Temperature Superconductors ◽  
Linear Temperature Dependence ◽  
Strongly Correlated ◽  
Linear Temperature ◽  
Strongly Correlated Materials ◽  
Starting Point ◽  
Wide Range ◽  
Degenerate Regime

Strange or bad metallic transport, defined by incompatibility with the conventional quasiparticle picture, is a theme common to many strongly correlated materials, including high-temperature superconductors. The Hubbard model represents a minimal starting point for modeling strongly correlated systems. Here we demonstrate strange metallic transport in the doped two-dimensional Hubbard model using determinantal quantum Monte Carlo calculations. Over a wide range of doping, we observe resistivities exceeding the Mott-Ioffe-Regel limit with linear temperature dependence. The temperatures of our calculations extend to as low as 1/40 of the noninteracting bandwidth, placing our findings in the degenerate regime relevant to experimental observations of strange metallicity. Our results provide a foundation for connecting theories of strange metals to models of strongly correlated materials.

A SINGLE HOLE IN THE TWO-DIMENSIONAL INFINITE-U HUBBARD MODEL IN AN ORBITAL MAGNETIC FIELD

1994 ◽  
Vol 08 (06) ◽  
pp. 707-725
Author(s):  
S. V. MESHKOV ◽  
J. C. ANGLÈS D'AURIAC
Keyword(s):  
Magnetic Field ◽  
Monte Carlo ◽  
Hubbard Model ◽  
Ground State ◽  
Quantum Monte Carlo ◽  
Applied Field ◽  
Monte Carlo Algorithm ◽  
Two Dimensional ◽  
Thermodynamical Properties ◽  
Single Hole

Using an original Quantum Monte Carlo algorithm, we study the thermodynamical properties of a single hole in the two-dimensional infinite-U Hubbard model at finite temperature. We investigate the energy and the spin correlators as a function of an external orbital magnetic field. This field is found to destroy the Nagaoka ferromagnetism and to induce chirality in the spin background. The applied field is partially screened by a fictitious magnetic field coming from the chirality. Our algorithm allows us to reach a temperature low enough to discuss the ground state properties of the model.

scholarly journals Solutions of the Two-Dimensional Hubbard Model: Benchmarks and Results from a Wide Range of Numerical Algorithms

2015 ◽  
Vol 5 (4) ◽  
Author(s):  
J. P. F. LeBlanc ◽  
Andrey E. Antipov ◽  
Federico Becca ◽  
Ireneusz W. Bulik ◽  
Garnet Kin-Lic Chan ◽  
...  
Keyword(s):  
Hubbard Model ◽  
Numerical Algorithms ◽  
Two Dimensional ◽  
Wide Range
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