Conditions for a ferromagnetic ground state of Ising and Heisenberg models with an external magnetic field

1981 ◽  
Vol 24 (5) ◽  
pp. 2570-2576 ◽  
Author(s):  
H. P. Bader ◽  
R. Schilling
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Ground State ◽  
Heisenberg Models ◽  
Ferromagnetic Ground State

Theory of ground-state switching in an array of magnetic nanodots by application of a short external magnetic field pulse

2013 ◽  
Vol 87 (13) ◽  
Author(s):  
Roman Verba ◽  
Vasil Tiberkevich ◽  
Konstantin Guslienko ◽  
Gennadiy Melkov ◽  
Andrei Slavin
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Ground State ◽  
Magnetic Field Pulse ◽  
Field Pulse ◽  
Magnetic Nanodots ◽  
State Switching

SPIN-SPLITTING OF THE BOUND POLARON'S GROUND STATE BINDING ENERGY INDUCED BY THE RASHBA SPIN–ORBIT INTERACTION UNDER THE PERPENDICULAR MAGNETIC FIELD

2008 ◽  
Vol 22 (12) ◽  
pp. 1923-1932
Author(s):  
JIA LIU ◽  
ZI-YU CHEN
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Binding Energy ◽  
Ground State ◽  
Spin Splitting ◽  
Perpendicular Magnetic Field ◽  
Spin Orbit ◽  
Ground State Binding Energy ◽  
Bound Polaron ◽  
Rashba Spin

The influence of a perpendicular magnetic field on a bound polaron near the interface of a polar–polar semiconductor with Rashba effect has been investigated. The material is based on a GaAs / Al x Ga 1-x As heterojunction and the Al concentration varying from 0.2 ≤ x ≤ 0.4 is the critical value below which the Al x Ga 1-x As is a direct band gap semiconductor.The external magnetic field strongly altered the ground state binding energy of the polaron and the Rashba spin–orbit (SO) interaction originating from the inversion asymmetry in the heterostructure splitting of the ground state binding energy of the bound polaron. How the ground state binding energy will be with the change of the external magnetic field, the location of a single impurity and the electron area density have been shown in this paper, taking into account the SO coupling. The contribution of the phonons are also considered. It is found that the spin-splitting states of the bound polaron are more stable, and, in the condition of weak magnetic field, the Zeeman effect can be neglected.

THE GROUND-STATE PHASE DIAGRAMS OF THE SPIN-2 ISING MODEL

2007 ◽  
Vol 21 (31) ◽  
pp. 5265-5274 ◽  
Author(s):  
AHMET ERDİNÇ
Keyword(s):  
Magnetic Field ◽  
Ising Model ◽  
External Magnetic Field ◽  
Phase Diagrams ◽  
Crystal Field ◽  
Ground State ◽  
Exchange Interactions ◽  
Nearest Neighbors ◽  
Biquadratic Exchange ◽  
Model Hamiltonian

The ground-state phase diagrams are obtained for the spin-2 Ising model Hamiltonian with bilinear and biquadratic exchange interactions and a single-ion crystal field. The interactions are assumed to be only between nearest-neighbors. Obtained phase diagrams are presented in the (Δ,J), (K,J), (Δ/J,K/J), (Δ/|J|,K/|J|), (Δ/|K|,J/|K|), (H/J,Δ/J), (H/|J|,Δ/|J|), (H/J,K/J), and (H/|J|,K/|J|) planes where J, K, Δ, and H are the bilinear, biquadratic exchange interactions, the single-ion crystal field, and the external magnetic field, respectively. The influence of the external magnetic field on the spin configurations is investigated.

LANDAU LEVELS AND VERTEX OPERATIONS FOR ANYONS

1991 ◽  
Vol 06 (30) ◽  
pp. 2819-2826 ◽  
Author(s):  
GERALD V. DUNNE ◽  
ALBERTO LERDA ◽  
CARLO A. TRUGENBERGER
Keyword(s):  
Magnetic Field ◽  
Angular Momentum ◽  
External Magnetic Field ◽  
String Theory ◽  
Ground State ◽  
Correlation Functions ◽  
Landau Levels ◽  
Vertex Operators ◽  
Many Body

We construct exact many-body eigenstates of both energy and angular momentum for the N-anyon problem in an external magnetic field. We show that such states span the full ground state eigenspace and arise as correlation functions of Fubini-Veneziano vertex operators of string theory.

GROUND STATE OF N HARMONICALLY BOUND ANYONS IN A MAGNETIC FIELD

1992 ◽  
Vol 07 (38) ◽  
pp. 3593-3600
Author(s):  
R. CHITRA
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Harmonic Oscillator ◽  
Ground State ◽  
Harmonic Frequency ◽  
Oscillator Potential ◽  
Harmonic Oscillator Potential ◽  
Thomas Fermi ◽  
Large N ◽  
The Magnetic Field

The properties of the ground state of N anyons in an external magnetic field and a harmonic oscillator potential are computed in the large-N limit using the Thomas-Fermi approximation. The number of level crossings in the ground state as a function of the harmonic frequency, the strength and the direction of the magnetic field and N are also studied.

The ground state of rhombohedral crystals in an external magnetic field

1980 ◽  
Vol 72 (10) ◽  
pp. 5649-5655 ◽  
Author(s):  
A. K. Theophilou ◽  
S. Thanos
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Ground State

THE GROUND STATE OF QUANTUM RINGS IN A MAGNETIC FIELD

2006 ◽  
Vol 20 (23) ◽  
pp. 1443-1451
Author(s):  
YI-MIN LIU ◽  
GANG-MING HUANG ◽  
TING-YUN SHI
Keyword(s):  
Magnetic Field ◽  
Angular Momentum ◽  
External Magnetic Field ◽  
Effective Mass ◽  
Ground State ◽  
Geometric Configuration ◽  
Density Functions ◽  
Specific Group ◽  
Quantum Rings

The ground state of semiconductor quantum rings (QRs) in the presence of an external magnetic field B is theoretically analyzed. By numerically diagonalizing the effective-mass Hamiltonian of the QRs, the energy and wavefunction of the ground state are obtained. It is found that the energy oscillates as B increases. The evolution of the angular momentum L0 and the spin S0 of the ground state in accord with B is revealed. We depict the geometric configuration of the ground state via density functions. Based on an analysis of the wavefunction, it is shown that each configuration is accessible only to a specific group of states having specific L0 and S0.

Influence of magnetic field and Rashba spin–orbit coupling on strong-coupling magnetopolarons in quantum disks

2014 ◽  
Vol 28 (27) ◽  
pp. 1450185
Author(s):  
Wei Xin ◽  
Chao Han ◽  
Eerdunchaolu
Keyword(s):  
Magnetic Field ◽  
External Magnetic Field ◽  
Interaction Energy ◽  
Ground State ◽  
State Interaction ◽  
Orbit Coupling ◽  
Spin Orbit Coupling ◽  
Spin Orbit ◽  
Phonon Interaction ◽  
Rashba Spin

On the basis of Lee–Low–Pines (LLP) unitary transformation, the influence of external magnetic field, Rashba spin–orbit coupling and quantum size effect on the ground-state interaction energy of strong-coupling magnetopolarons in quantum disks (QDs) is studied by using the Tokuda improved linear combine operator method. The results show that the ground-state interaction energy of magnetopolarons consists of four parts: the energy caused by the confinement potential of QDs, interaction energy between the electron and external magnetic field, electron and longitudinal-optical (LO) phonon interaction energy and additional term of Rashba effect originating from phonons. The electron–LO phonon interaction energy Ee- ph and additional term of Rashba effect are always negative; the absolute value |Ee- ph | increases with increasing transverse confinement strength ω0, cyclotron frequency of external magnetic field ωc and electron–LO phonon coupling strength α, but decreases with increasing the thickness of QDs L; the state properties of magnetopolarons are closely linked with the sign of the ground-state interaction energy of magnetopolarons E int and change of E int with ωc, ω0, α and L. In addition, the vibration frequency of magnetopolarons λ increases with increasing ωc, ω0 and α, but decreases with increasing L. For the ground state of magnetopolarons in QDs, the electron–LO phonon interaction plays a significant role, meanwhile, the influence of Rashba spin–orbit coupling effect cannot be ignored.

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