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Pantić, M.; Kapor, D.; Radošević, Slobodan; Mali, Petar

doi:10.1016/j.ssc.2013.12.007

Cited by 28 publications

(22 citation statements)

References 37 publications

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“…Due to the isomorphism of the spin and Paulion Hilbert spaces on every lattice site and the relations in Equations (3) and (4), the original problem of exciton dynamics governed by Equation (1) can be completely mapped onto the equivalent effective spin model in Equation (2). It should be noted that this correspondence is purely formal—it will allow us to investigate the exciton system with the help of a vast number of existing theoretical tools developed for spin systems [21,22,23,24,25,26,27,28,29]. According to Reference [5], the Pauli Hamiltonian of Equation (1), which is as we have shown here equivalent to the anisotropic Heisenberg Hamiltonian of Equation (2), can be used in the description of pentacene.…”

Section: Model Hamiltonian and Pentacene Structurementioning

confidence: 99%

Dynamics of Frenkel Excitons in Pentacene

et al. 2018

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The dispersion relation for noninteracting excitons and the influence of perturbative corrections are examined in the case of pentacene structure. The values of exchange integrals are determined by nonlinear fits to the experimental dispersion data, obtained by the inelastic electron scattering reported in recent experiments. We obtain theoretical dispersion curves along four different directions in the Brillouin zone which possess the same periodicity as the experimental data. We also show that perturbative corrections are negligible since the exciton gap in the dispersion relation is huge in comparison to the exchange integrals.

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Section: Model Hamiltonian and Pentacene Structurementioning

confidence: 99%

Dynamics of Frenkel Excitons in Pentacene

et al. 2018

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“…Therefore, if we kept only the NN terms in Hamiltonian (1), the ground state would not be exactly the Neel state, due to the quantum fluctuations [46]. The examinations based on the comprehensive Hamiltonian of type (1) (see [21,[32][33][34][35])…”

Section: Model Hamiltonian Green's Function Determination and Main Resultsmentioning

confidence: 99%

Anisotropy Influence on the Striped Antiferromagnetism of a Frustrated Heisenberg Model: An Application to Iron Pnictide Materials

Pantić

Rutonjski

Mali

et al. 2016

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Motivated by several experimental studies of magnetic compounds related to iron pnictides, we examine thermodynamic properties of anisotropic J1a - J1b - Jc - J2 Heisenberg antiferromagnetic model. Our calculations are based on the two-time temperature Green's functions within several well-known decoupling approximations. We obtain excitation spectrum, correlation functions and the analytic expression for the critical temperature and compare our results to the existing experimental data. Results presented here could be of a great importance in the further investigations of similar magnetic systems.

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“…J1-Ferromagnetic (0, 0, 0) (π, π, π) PFFRG * 0.56(2) Exact Diagonalization * 0.568 Coupled Cluster Method * 0.579 Rotation-invariant Green's function method [30] 0.68 Random phase approximation [29] 0.6799 J1-Antiferromagnetic (2π, 0, 0) (π, π, π) PFFRG * 0.70(2) Coupled Cluster Method [34] 0.704 Exact Diagonalization [24] 0.7 Non-linear spin-wave theory [32] 0.705 Random phase approximation [33] 0.72 Linked Cluster Series expansions [31] 0.705 (5) TABLE III. The critical value J c 2 /|J1| of the transition between the FM/Néel and the stripe order obtained from PFFRG and compared to different methods for the S = 1/2 J1-J2 Heisenberg model on the BCC lattice with J3 = 0.…”

Section: B Quantum Phase Diagrammentioning

confidence: 99%

Quantum paramagnetism and helimagnetic orders in the Heisenberg model on the body centered cubic lattice

et al. 2019

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We investigate the spin S = 1/2 Heisenberg model on the body centered cubic lattice in the presence of ferromagnetic and antiferromagnetic nearest-neighbor J1, second-neighbor J2, and third-neighbor J3 exchange interactions. The classical ground state phase diagram obtained by a Luttinger-Tisza analysis is shown to host six different (noncollinear) helimagnetic orders in addition to ferromagnetic, Néel, stripe and planar antiferromagnetic orders. Employing the pseudofermion functional renormalization group (PFFRG) method for quantum spins (S = 1/2) we find an extended nonmagnetic region, and significant shifts to the classical phase boundaries and helimagnetic pitch vectors caused by quantum fluctuations while no new long-range dipolar magnetic orders are stabilized. The nonmagnetic phase is found to disappear for S = 1. We calculate the magnetic ordering temperatures from PFFRG and quantum Monte Carlo methods, and make comparisons to available data. arXiv:1902.01179v1 [cond-mat.str-el]

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Phase diagram of spin-12 quantum Heisenberg J

Cited by 28 publications

References 37 publications

Dynamics of Frenkel Excitons in Pentacene

Dynamics of Frenkel Excitons in Pentacene

Anisotropy Influence on the Striped Antiferromagnetism of a Frustrated Heisenberg Model: An Application to Iron Pnictide Materials

Quantum paramagnetism and helimagnetic orders in the Heisenberg model on the body centered cubic lattice

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