scholarly journals Topological Properties in a Λ/V-Type Dice Model

Crystals ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 467
Author(s):  
Shujie Cheng ◽  
Xianlong Gao
Keyword(s):  
Energy Spectrum ◽  
Phase Diagrams ◽  
State Energy ◽  
Nearest Neighbor ◽  
Edge State ◽  
Metal Phase ◽  
Topological Properties ◽  
Energy Bands ◽  
Chern Numbers ◽  
Dice Model

We studied a non-interacting Λ/V-type dice model composed of three triangular sublattices. By considering the isotropic nearest-neighbor hoppings and the next-nearest-neighbor hoppings with the phase, as well as the quasi-staggered on-site potential, we acquired the full phase diagrams under the different fillings of the energy bands. There are abundant topological non-trivial phases with different Chern numbers C=±1, as well as higher ones ±2,±3 and a metal phase in several regimes. In addition, we also checked the bulk–edge correspondence of the system by analyzing the edge-state energy spectrum.

scholarly journals ENTANGLEMENT AND FRUSTRATION IN ORDERED SYSTEMS

2003 ◽  
Vol 01 (04) ◽  
pp. 465-477 ◽  
Author(s):  
MICHAEL M. WOLF ◽  
FRANK VERSTRAETE ◽  
J. IGNACIO CIRAC
Keyword(s):  
Ground State ◽  
State Energy ◽  
Nearest Neighbor ◽  
Bell Inequalities ◽  
Harmonic Oscillators ◽  
Neighbor Interaction ◽  
Gaussian States ◽  
Classical Systems ◽  
Entanglement Of Formation ◽  
Starting Point

This article reviews and extends recent results concerning entanglement and frustration in multipartite systems which have some symmetry with respect to the ordering of the particles. Starting point of the discussion are Bell inequalities: their relation to frustration in classical systems and their satisfaction for quantum states which have a symmetric extension. We then discussed how more general global symmetries of multipartite systems constrain the entanglement between two neighboring particles. We prove that maximal entanglement (measured in terms of the entanglement of formation) is always attained for the ground state of a certain nearest neighbor interaction Hamiltonian having the considered symmetry with the achievable amount of entanglement being a function of the ground state energy. Systems of Gaussian states, i.e. quantum harmonic oscillators, are investigated in more detail and the results are compared to what is known about ordered qubit systems.

Transfer Integrals and Band Structures in (Et)2X Salts

1989 ◽  
Vol 173 ◽  
Author(s):  
Oliver H. Leblanc ◽  
Margaret L. Blohm ◽  
Richard P. Messmer
Keyword(s):  
Low Temperature ◽  
Nearest Neighbor ◽  
Spherical Wave ◽  
Tight Binding ◽  
Ab Initio Method ◽  
Energy Bands ◽  
Hubbard Hamiltonian ◽  
Transfer Integrals ◽  
Semi Empirical ◽  
Very Low Temperature

ABSTRACTTransfer integrals (tij) between pairs of nearest neighbor ET molecules were calculated by an ab initio method. Tight-binding one-electron energy bands constructed from the tij are similar to those previously calculated by Mori and by Whangbo and their coworkers by semi-empirical, extended Hückel methods, but quite different from those found by Kübler et al. in β-(ET)2I3 using the augmented spherical wave (ASW) method. However, all these band models are suspect. The Hubbard on-site repulsion parameter U is estimated to be about twice the band widths, indicating that a full treatment of the Hubbard hamiltonian is needed. Also, polaron effects appear to control transport except at very low temperature.

scholarly journals Progress Review on Topological Properties of Heusler Materials

2020 ◽  
Vol 213 ◽  
pp. 02016
Author(s):  
Zhi Lin
Keyword(s):  
Hall Effect ◽  
Surface States ◽  
Anomalous Hall Effect ◽  
Edge State ◽  
Chiral Anomaly ◽  
Dirac Fermion ◽  
High Symmetry ◽  
Heusler Compounds ◽  
Topological Properties ◽  
Topological State

Starting from crystal, electronic and magnetic structures of Heusler compounds, this paper studies the new topological materials related to Heusler compounds and their topological properties, such as anomalous Hall effect, skyrmions, chiral anomaly, Dirac fermion, Weyl fermion, transverse Nernst thermoelectric effect, thermal spintronics and topological surface states. It can be discovered that the topological state of Heusler compound can be well protected due to its high symmetry, thus producing rich topological properties. Heusler materials belonged to Weyl semimetals usually have strong anomalous Hall effect, and the Heusler materials with doping or Anomalous Nernst Effect (ANE) usually have higher thermoelectric figure of merit. These anomalous effects are closely related to the strong spin–orbit interaction. In application, people can use the non-dissipative edge state of quantum anomalous Hall effect to develop a new generation of low-energy transistors and electronic devices. The conversion efficiency of thermoelectric materials can be improved by ANE, and topological superconductivity can be used to promote the progress of quantum computation.

scholarly journals ESR Study on the Excited State Energy Spectrum of SrCu2(BO3)2–A Central Role of Multiple-Triplet Bound States–

2003 ◽  
Vol 72 (12) ◽  
pp. 3243-3253 ◽  
Author(s):  
Hiroyuki Nojiri ◽  
Hiroshi Kageyama ◽  
Yutaka Ueda ◽  
Mitsuhiro Motokawa
Keyword(s):  
Excited State ◽  
Energy Spectrum ◽  
Bound States ◽  
State Energy ◽  
Excited State Energy

Alloy Chemical Comparison of the Refractory Metal - Noble Metal Phase Diagrams T5-T10 (T5 = V, Nb, Ta; T10 = Pd, Pt)

1982 ◽  
Vol 19 ◽  
Author(s):  
R. Waterstrat ◽  
B.C. Giessen
Keyword(s):  
Phase Diagrams ◽  
Noble Metal ◽  
Refractory Metal ◽  
Metal Alloy ◽  
Metal Phase

ABSTRACTThe six T5-Tl0 metal alloy phase diagrams containing Pd or Pt have now all been established. The alloy phases occurring in these systems are tabulated and reviewed here with respect to their structures.

Thermodynamic Properties of an In-Phase Flux Antiferromagnetic Spin Coupled Heisenberg Model on a Square Lattice

SPIN ◽  
2018 ◽  
Vol 08 (04) ◽  
pp. 1830001
Author(s):  
E. Mainimo ◽  
N. Ibrahim Famenyi
Keyword(s):  
Energy Spectrum ◽  
Specific Heat ◽  
Thermodynamic Parameters ◽  
Heisenberg Model ◽  
State Energy ◽  
Spontaneous Magnetization ◽  
Exchange Interactions ◽  
Spin Model ◽  
Square Lattice ◽  
Antiferromagnetic Spin

Using the two-dimensional Jordan–Wigner Fermionization procedure, we calculate the energy spectrum of the in-phase flux antiferromagnetically spin-1/2 coupled Heisenberg model in a square lattice, the formalism used introduces the notion of isotropic parameters. The energy spectrum is analyzed for various regimes of the exchange interactions and the isotropic parameters. The thermodynamic parameters of the lattice, notably the ground state energy, the free energy, mean energy, entropy and specific heat are calculated. It is seen that the specific heat undergoes a phase transition at a temperature below the critical temperature due to spontaneous magnetization. Its entropy for homogeneous and completely isotropic regime is compared for two regimes of the exchange interaction and it is observed that the entropy decreases with an increase in the coupling strength. All the thermodynamic parameters calculated for this spin model are seen to be in conformity with the principles and laws of Statistical Thermodynamics.

scholarly journals Complete catalog of ground-state diagrams for the general three-state lattice-gas model with nearest-neighbor interactions on a square lattice

2019 ◽  
Vol 21 (11) ◽  
pp. 6216-6223 ◽  
Author(s):  
Daniel Silva ◽  
Per Arne Rikvold
Keyword(s):  
Phase Diagrams ◽  
Ground State ◽  
Lattice Gas ◽  
Nearest Neighbor ◽  
Square Lattice ◽  
Temperature Phase ◽  
Zero Temperature ◽  
Dimensional Parameter ◽  
State Diagrams ◽  
Solid Foundation

The fifteen topologically different zero-temperature phase diagrams in the model's full, five-dimensional parameter space provide a solid foundation for studies at finite temperatures.

GROUND STATE OF THE 2D EXTENDED HUBBARD MODEL WITH MORE THAN NEAREST-NEIGHBOR INTERACTIONS

2012 ◽  
Vol 26 (29) ◽  
pp. 1250156 ◽  
Author(s):  
S. HARIR ◽  
M. BENNAI ◽  
Y. BOUGHALEB
Keyword(s):  
Phase Diagram ◽  
Hubbard Model ◽  
Ground State ◽  
State Energy ◽  
Nearest Neighbor ◽  
Finite Size ◽  
Square Lattice ◽  
Extended Hubbard Model ◽  
Eigenvalues And Eigenvectors ◽  
Repulsion Energy

We investigate the ground state phase diagram of the two dimensional Extended Hubbard Model (EHM) with more than Nearest-Neighbor (NN) interactions for finite size system at low concentration. This EHM is solved analytically for finite square lattice at one-eighth filling. All eigenvalues and eigenvectors are given as a function of the on-site repulsion energy U and the off-site interaction energy Vij. The behavior of the ground state energy exhibits the emergence of phase diagram. The obtained results clearly underline that interactions exceeding NN distances in range can significantly influence the emergence of the ground state conductor–insulator transition.

SOME REMARKS ON THE THEORY OF AN ELECTRON ON BINARY QUASIPERIODIC LATTICES

1994 ◽  
Vol 08 (15) ◽  
pp. 1931-1964 ◽  
Author(s):  
KAZUMOTO IGUCHI
Keyword(s):  
Energy Spectrum ◽  
Julia Set ◽  
Cantor Set ◽  
Simple Approach ◽  
Arbitrary Positive Integer ◽  
Energy Bands ◽  
Invariant Surface ◽  
Band Center ◽  
Trace Map ◽  
Scaling Transformation

Some remarks on the theory of an electron on binary quasiperiodic lattices are presented herein. We classify all the binary quasiperiodic lattices that are constructed by a class of scaling transformations: B→A, A→AnB, where n is an arbitrary positive integer at each stage of the scaling transformation, into three types by means of the scaling transformation itself. We give a simple approach to generate a Cantor-set type energy spectrum by the generic trace map on an invariant surface, I=x2+y2+z2−2xyz−1. The Cantor-set type energy spectrum is a result of the existence of the noncompact invariant surface of the invariant I>0. The energy bands correspond to the nonescaping points of the generic trace map on the invariant surface, which are identified with the Julia set of the generic trace map. The density of states and the wavefunction at the band center are discussed, and we are able to classify them into three types respectively by means of its exponents.

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