VARIATIONAL STUDY OF THE PAIR HOPPING MODEL

1989 ◽  
Vol 03 (12) ◽  
pp. 1765-1781 ◽  
Author(s):  
P. Fazekas
Keyword(s):  
Tight Binding ◽  
Wave Functions ◽  
Nearest Neighbour ◽  
Electron Pairs ◽  
Gutzwiller Approximation ◽  
Variational Treatment ◽  
Variational Study ◽  
Hopping Model ◽  
Pair Hopping ◽  
Paired State

We study the ground state of a Hamiltonian introduced by Kolb and Penson for modelling situations in which small electron pairs are formed. The Hamiltonian consists of a tight binding band term, and a term describing the nearest neighbour hopping of electron pairs. We give a Gutzwiller-type variational treatment, first with a single-parameter Ansatz treated in the single site Gutzwiller approximation, and then with more complicated trial wave functions, and an improved Gutzwiller approximation. The calculation yields a transition from a partially paired normal state, in which the spin susceptibility has a diminished value, into a fully paired state.

Low-lying surface vibrations in the pair-hopping model

1994 ◽  
Vol 49 (1) ◽  
pp. 552-554 ◽  
Author(s):  
R. A. Broglia ◽  
F. Barranco ◽  
G. F. Bertsch ◽  
E. Vigezzi
Keyword(s):  
Surface Vibrations ◽  
Hopping Model ◽  
Pair Hopping

scholarly journals Phase diagram of the $\mathbb{Z}_3$-Fock parafermion chain with pair hopping

2020 ◽  
Vol 3 (2) ◽  
Author(s):  
Iman Mahyaeh ◽  
Jurriaan Wouters ◽  
Dirk Schuricht
Keyword(s):  
Phase Diagram ◽  
Single Particle ◽  
Correlation Functions ◽  
Energy Gap ◽  
Central Charge ◽  
Entanglement Entropy ◽  
Tight Binding ◽  
Tight Binding Model ◽  
Binding Model ◽  
Pair Hopping

We study a tight binding model of \mathbb{Z}_3ℤ3-Fock parafermions with single-particle and pair-hopping terms. The phase diagram has four different phases: a gapped phase, a gapless phase with central charge \boldsymbol{c=2}𝐜=2, and two gapless phases with central charge \boldsymbol{c=1}𝐜=1. We characterise each phase by analysing the energy gap, entanglement entropy and different correlation functions. The numerical simulations are complemented by analytical arguments.

scholarly journals Accelerating scientific discovery through computation and visualization - III. Tight-binding wave functions for quantum dots

2008 ◽  
Vol 113 (3) ◽  
pp. 131 ◽  
Author(s):  
James S. Sims ◽  
William L. George ◽  
Terence J. Griffin ◽  
John C. Hagedorn ◽  
Howard K. Hung ◽  
...  
Keyword(s):  
Quantum Dots ◽  
Scientific Discovery ◽  
Tight Binding ◽  
Wave Functions

scholarly journals Tight-binding Central Interaction Model for the Band Structure of Silicon

1984 ◽  
Vol 37 (4) ◽  
pp. 407
Author(s):  
GP Betteridge
Keyword(s):  
Band Structure ◽  
Tight Binding ◽  
Interaction Model ◽  
Diamond Lattice ◽  
Nearest Neighbour ◽  
Tight Binding Model ◽  
Binding Model ◽  
Central Interaction

We consider a simple tight-binding model involving all interactions between first and second nearest-neighbour (n.n.) bonds in the diamond lattice. We show that the band structure may be solved analytically in the central approximation in which all second n.n. bond interactions of the same type, for example all bonding: bonding or all bonding: antibonding interactions, are considered equal. The k dependence of the solution is given in terms of the corresponding s-band eigenvalues, which are determined by the topology of the structure.

scholarly journals Electron-hole correlations in semiconductor quantum dots with tight-binding wave functions

2001 ◽  
Vol 63 (19) ◽  
Author(s):  
Seungwon Lee ◽  
Lars Jönsson ◽  
John W. Wilkins ◽  
Garnett W. Bryant ◽  
Gerhard Klimeck
Keyword(s):  
Quantum Dots ◽  
Tight Binding ◽  
Semiconductor Quantum Dots ◽  
Wave Functions ◽  
Electron Hole

Lone Pair Interactions in Zintl Phases and Intermetallic Compounds: Influence on Electronic Properties in Stannides and Plumbides

1998 ◽  
Vol 547 ◽  
Author(s):  
Thomas F. Fässler
Keyword(s):  
Intermetallic Compounds ◽  
Chemical Bond ◽  
Tight Binding ◽  
Lone Pair ◽  
Real Space ◽  
Localized States ◽  
Zintl Phases ◽  
Electron Pairs ◽  
Lone Pairs ◽  
Lone Pair Interactions

AbstractThe phases K6Sn23Bi2, K6Sn25, NaSn5, BaSn3, BaSn5, and K5Pb24 depict the structural transition from Zintl phases with localized chemical bonds to typical intermetallic compounds which may even have superconducting properties. The question of the nature of the chemical bond in these compounds is studied with the help of quantum mechanical calculations. Tight binding band structure calculations and real space representations using the Electron Localization Function (ELF) show that free electron pairs play a crucial role for the description of the chemical bond in polar intermetallic compounds. Interactions between lone pairs have a dominant influence on the electronic structures. The coincident appearance of quasi-molecular localized states in form of lone pairs and disperse delocalized bands at the Fermi level EF is discussed with respect to a ‘chemical view’ of the superconductivity observed for BaSn3, BaSn5, and K5Pb24.

scholarly journals GRAPHENE IN THE QUANTUM HALL REGIME: EFFECTS OF VACANCIES, SUBLATTICE POLARIZATION AND DISORDER

2009 ◽  
Vol 23 (12n13) ◽  
pp. 2618-2627 ◽  
Author(s):  
ANA L. C. PEREIRA ◽  
PETER A. SCHULZ
Keyword(s):  
Quantum Hall ◽  
Tight Binding ◽  
Wave Functions ◽  
Hall Resistance ◽  
Monolayer Graphene ◽  
Binding Model ◽  
Quantum Hall Regime ◽  
Hall Regime ◽  
Valley Polarization ◽  
Disorder Effect

We investigate the effects of vacancies, disorder and sublattice polarization on the electronic properties of a monolayer graphene in the quantum Hall regime. Energy spectra as a function of magnetic field and the localization properties of the states within the graphene Landau levels (LLs) are calculated through a tight-binding model. We first discuss our results considering vacancies in the lattice, where we show that vacancies introduce extra levels (or well-defined bands) between consecutive LLs. An striking consequence here is that extra Hall resistance plateaus are expected to emerge when an organized vacancy superlattice is considered. Secondly, we discuss the anomalous localization properties we have found for the lowest LL, where an increasing disorder is shown to enhance the wave functions delocalization (instead of inducing localization). This unexpected effect is shown to be directly related to the way disorder increasingly destroys the sublattice (valley) polarization of the states in the lowest LL. The reason why this anomalous disorder effect occurs only for the zero-energy LL is that, in absence of disorder, only for this level all the states are sublattice polarized, i.e., their wave functions have amplitudes in only one of the sublattices.

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