Analytic model for low energy excitation states and phase transitions in spin-ice systems

2017 ◽  
Vol 29 (15) ◽  
pp. 155803 ◽  
Author(s):  
F I López-Bara ◽  
F López-Aguilar
Keyword(s):  
Phase Transitions ◽  
Low Energy ◽  
Analytic Model ◽  
Spin Ice ◽  
Energy Excitation

scholarly journals A Model of Two Quantum Fluids for the Low Energy Excited States of the Systems with Entities That Mimic the Magnetic Monopoles

Fluids ◽  
2021 ◽  
Vol 6 (9) ◽  
pp. 324
Author(s):  
Fernando M. López-Aguilar ◽  
Fernando I. López-Bara
Keyword(s):  
Specific Heat ◽  
Excited States ◽  
Magnetic Monopoles ◽  
Low Energy ◽  
Quantum Fluids ◽  
Spin Ice ◽  
Energy Excitation ◽  
Magnetic Dipoles ◽  
Plasma State ◽  
Good Concordance

The low energy excitation states in frustrated magnetic structures can generate quasiparticles that behave as if they were magnetic charges. These excited states produce, in the so-called spin-ice materials, two different peaks of specific heat at temperatures less than 1.5 K. In this paper, we consider that the first structure is caused by the formation of fluid of magnetic dipoles configured by the dumbbell model with a boson nature in consonance with that described by Witten for mesons. The second structure, wider than the first one, corresponds to a plasma state that comes from the breaking of a great number of dipoles, which provokes the appearance of free magnetic charges, which constitute a cool magnetic plasma fluid. In this paper, we determine thermodynamic analytical functions: the thermo-potential and internal energy and their respective derivative physical magnitudes: entropy, and magnetic specific heat. We obtain results in a good concordance with the experimental data, which allow us to explain the phase transitions occurred in these spin-ice materials at very low temperatures.

scholarly journals Magnetic-charge ordering and phase transitions in monopole-conserved square spin ice

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Y.-L. Xie ◽  
Z.-Z. Du ◽  
Z.-B. Yan ◽  
J.-M. Liu
Keyword(s):  
Phase Transitions ◽  
Magnetic Charge ◽  
Charge Ordering ◽  
Spin Ice

Low-energy excitation spectra of the system KY(MoO4)2-KEr(MoO4)2

1996 ◽  
Vol 46 (S5) ◽  
pp. 2687-2688
Author(s):  
Vladimir I. Kut'ko ◽  
Nina M. Nesterenko ◽  
Yuriy N. Kharchenko
Keyword(s):  
Low Energy ◽  
Excitation Spectra ◽  
Energy Excitation

Low-Energy Excitation in β-Cu2Se

1989 ◽  
Vol 58 (9) ◽  
pp. 3061-3064 ◽  
Author(s):  
Takashi Sakuma ◽  
Kaoru Shibata
Keyword(s):  
Low Energy ◽  
Energy Excitation

Inelastic neutron scattering and low-energy excitation of amorphous SF6 hydrate prepared by vapor-deposition technique

2003 ◽  
Vol 81 (1-2) ◽  
pp. 107-114 ◽  
Author(s):  
O Yamamuro ◽  
T Matsuo ◽  
I Tsukushi ◽  
N Onoda-Yamamuro
Keyword(s):  
Neutron Scattering ◽  
Inelastic Neutron Scattering ◽  
Inelastic Neutron ◽  
Annealed Sample ◽  
Low Energy ◽  
Energy Excitation ◽  
Hydrogen Bond Formation ◽  
Crystalline Sample ◽  
Two Samples ◽  
Vapor Deposition Technique

Amorphous SF6 hydrate (SF6·17H2O) was prepared by depositing the mixed vapor onto a substrate kept at about 8 K. The inelastic neutron-scattering spectra of the as-deposited sample and those annealed at about 120 and 150 K were measured at 50 K in the energy range below 100 meV. The first two samples were considered to be in amorphous states while the third one was in a crystalline state. The librational frequency of the water molecule (at around 60 meV) is smaller in the order of (as-deposited sample) < (annealed sample) < (crystalline sample). This indicates that the strength of the intermolecular hydrogen bonds is (crystalline sample) > (annealed sample) > (as-deposited sample). The spectra below 10 meV were compared with our previous data of pure vapor-deposited amorphous ices and those doped with methanol (CD3OH). The low-energy excitation (E < 6 meV) differed drastically depending on the dopants, i.e., the scattering intensity was enhanced by methanol doping but reduced by SF6 doping. This may be because the hydrogen-bond formation was hindered by methanol doping but promoted rather more by SF6 doping because of the hydrophobic interaction as in clathrate hydrates. PACS Nos.: 61.12Ex, 63.50tx

ROLE OF THE ELECTRON–PHONON INTERACTION ON THE SPECTRAL DENSITY AND PSEUDOGAP IN CUPRATES

2002 ◽  
Vol 16 (23) ◽  
pp. 3465-3471
Author(s):  
I. CHAUDHURI ◽  
S. K. GHATAK
Keyword(s):  
Critical Temperature ◽  
Spectral Density ◽  
Low Energy ◽  
Phonon Interaction ◽  
Energy Excitation ◽  
Electron Phonon Interaction ◽  
Peak Structure ◽  
Electronic Model ◽  
Jahn Teller

The pseudogap structure in low energy excitation in cuprates appears below a temperature and the spectral density exhibits strong wave-vector dependence. An electronic model that emphasized the coupling of carrier in Cu-O with phonon is examined for pseudogap. The electron–phonon interaction originates from the modulation of on-site and hopping energy and leads to spontaneous Jahn–Teller-like distortion and pseudogap below a critical temperature. At low temperature the spectral density has two-peak structure about the Fermi level for all k along Γ-M whereas such structure exists along Γ-X for small k only. The magnitude of pseudogap shows strong k-dependence — maximum along Γ-M and vanishes along Γ-X. These features emphasize the role of electron–phonon interaction in formation of pseudogap.

scholarly journals Low Energy Excitation Spectra of Trapped Bose Condensates

1998 ◽  
Vol 93 (1) ◽  
pp. 211-235 ◽  
Author(s):  
L. You ◽  
W. Hoston ◽  
M. Lewenstein ◽  
M. Marinescu
Keyword(s):  
Low Energy ◽  
Excitation Spectra ◽  
Energy Excitation ◽  
Bose Condensates
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