The Laplacian Spectra of Small-World Networks

Mori, Fumito; Odagaki, Takashi

doi:10.1143/jpsj.73.3294

Cited by 12 publications

(15 citation statements)

References 20 publications

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“…3 (b), where the SbF 6 salt has larger value of V . This is consistent with the fact that the SbF 6 salt has larger transfer integrals along the diagonal q1 and q2 bonds, namely, larger overlap between the molecular orbitals, which results in larger values of intersite Coulomb repulsions [33], V q1 and V q2 , favoring the FCO pattern. The smooth evolution of phases with applied P suggests that the system follows along the arrow in Fig.…”

supporting

confidence: 83%

“…3 (b). Specifically, with applied P , transfer integrals reflecting the overlap between the molecular orbitals are more sensitive compared to the inter-site Coulomb repulsions, which are approximately a function of intermolecular distance [33]. Then, the variation of ground state with P is now given by FCO+2DAF (AFM 2 ) → FCO+SP (SP 2 ) → DM+SP(SP 1 ) → DM+2DAF (AFM 1 ) states, which agrees with the variation in Fig.…”

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confidence: 82%

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Tuning the Magnetic Dimensionality by Charge Ordering in the Molecular TMTTF Salts

et al. 2012

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We theoretically investigate the interplay between charge ordering and magnetic states in quasione-dimensional molecular conductors TMTTF2X, motivated by the observation of a complex variation of competing and/or coexisting phases. We show that the ferroelectric-type charge order increases two-dimensional antiferromagnetic spin correlation, whereas in the one-dimensional regime two different spin-Peierls states are stabilized. By using first-principles band calculations for the estimation for the transfer integrals and comparing our results with the experiments, we identify the controlling parameters in the experimental phase diagram to be not only the interchain transfer integrals but also the amplitude of the charge order.

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confidence: 83%

supporting

confidence: 82%

Tuning the Magnetic Dimensionality by Charge Ordering in the Molecular TMTTF Salts

et al. 2012

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“…In conventional single-orbital compounds, the bare Coulomb interactions are known to follow the Coulomb law as a function of the inter-molecular distance. 19,24) In addition, we find that the inter-fragment distance for the [001] interactions becomes shorter than that for the intra-molecular one, and then the interactions V exceed the intra-molecular interaction V 0 . This feature would be a key ingredient in obtaining the intra-molecular degree of freedom, and particularly for the ICO phenomena.…”

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confidence: 79%

Multi-Orbital Molecular Compound (TTM-TTP)I₃: Effective Model and Fragment Decomposition

et al. 2011

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The electronic structure of the molecular compound (TTM-TTP)I3, which exhibits a peculiar intramolecular charge ordering, has been studied using multi-configuration ab initio calculations. First we derive an effective Hubbard-type model based on the molecular orbitals (MOs) of TTM-TTP; we set up a two-orbital Hamiltonian for the two MOs near the Fermi energy and determine its full parameters: the transfer integrals, the Coulomb and exchange interactions. The tight-binding band structure obtained from these transfer integrals is consistent with the result of the direct band calculation based on density functional theory. Then, by decomposing the frontier MOs into two parts, i.e., fragments, we find that the stacked TTM-TTP molecules can be described by a two-leg ladder model, while the inter-fragment Coulomb energies are scaled to the inverse of their distances. This result indicates that the fragment picture that we proposed earlier [M.-L. Bonnet et al.: J. Chem. Phys. 132 (2010) 214705] successfully describes the low-energy properties of this compound.

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“…Another important difference from the predictions of the dimer model is that the values of the interactions, U m and V m , are vital for determining the parameters of the Heisenberg model. These are not well known at present and may differ between materials, but the best estimates suggest that U m t b1 and V m U m [12,[16][17][18].…”

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confidence: 95%

Dynamical Reduction of the Dimensionality of Exchange Interactions and the “Spin-Liquid” Phase of κ - (BEDT−TTF)2
Powell
¹
,
Kenny
²
,
Merino
³

2017
Phys. Rev. Lett.
19
0
17
0
1
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We show that the anisotropy of the effective spin model for the dimer Mott insulator phase of κ-ðBEDT-TTFÞ 2 X salts is dramatically different from that of the underlying tight-binding model. Intradimer quantum interference results in a model of coupled spin chains, where frustrated interchain interactions suppress long-range magnetic order. Thus, we argue, the "spin liquid" phase observed in some of these materials is a remnant of the Tomonaga-Luttinger physics of a single chain. This is consistent with previous experiments and resolves some outstanding puzzles. DOI: 10.1103/PhysRevLett.119.087204 Layered organic charge transfer salts show a wide range of exotic physics due to strong electronic correlations and geometrical frustration [1]. This includes unconventional superconductivity, incoherent metallic transport, multiferroicity, and antiferromagnetism. However, the putative spin liquid states in κ-ðBEDT-TTFÞ 2 Cu 2 ðCNÞ 3 [2], κ-ðBEDT-TTFÞ 2 Ag 2 ðCNÞ 3 [3] (henceforth, CuCN and AgCN, respectively), and β'-EtMe 3 Sb½PdðdmitÞ 2 2 [4] are, perhaps, the least understood of these.CuCN is usually discussed in terms of the nearly triangular Heisenberg model [1,5]. Here, we demonstrate that the theoretical arguments that lead to this model are fallacious. They fail to account for quantum interference within the ðBEDT-TTFÞ 2 dimer. We derive the correct low-energy model including these effects and show that it leads to an anisotropic triangular lattice in the quasi-onedimensional (Q1D) regime, J 1 > J 2 , Fig. 1(c). Thus, the spin model for the Mott dimer insulating phases of the organic charge transfer salts are remarkably similar to that describing Cs 2 CuBr 4 and Cs 2 CuCl 4 [6], where deconfined spinons have been observed [5,7]. Our results provide natural explanations for several previously puzzling experiments on the organics.Electronic structure calculations demonstrate that a single molecular orbital contributes to the low-energy process in the κ-ðBEDT-TTFÞ 2 X salts [1,[8][9][10], and that the band structure is described by the tight-binding "monomer model" sketched in Fig. 1(a) Fig. 1(a)], and ½i; j implies a pair of dimers such as tetramer 2.Kino and Fukuyama (KF) showed that for large enough U m an insulating phase emerges [8]. They argued that this could be understood as a dimer Mott insulator: if one integrates out the bonding combination of molecular orbitals, this leaves an effective half-filled model containing only the antibonding combination of molecular orbitals,

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The Laplacian Spectra of Small-World Networks

Cited by 12 publications

References 20 publications

Tuning the Magnetic Dimensionality by Charge Ordering in the Molecular TMTTF Salts

Tuning the Magnetic Dimensionality by Charge Ordering in the Molecular TMTTF Salts

Multi-Orbital Molecular Compound (TTM-TTP)I₃: Effective Model and Fragment Decomposition

Dynamical Reduction of the Dimensionality of Exchange Interactions and the “Spin-Liquid” Phase of κ - (BEDT−TTF)2
Powell
¹
,
Kenny
²
,
Merino
³

2017
Phys. Rev. Lett.
19
0
17
0
1
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The Laplacian Spectra of Small-World Networks

Cited by 12 publications

References 20 publications

Tuning the Magnetic Dimensionality by Charge Ordering in the Molecular TMTTF Salts

Tuning the Magnetic Dimensionality by Charge Ordering in the Molecular TMTTF Salts

Multi-Orbital Molecular Compound (TTM-TTP)I3: Effective Model and Fragment Decomposition

Dynamical Reduction of the Dimensionality of Exchange Interactions and the “Spin-Liquid” Phase of κ - (BEDT−TTF)2Powell1, Kenny2, Merino3 2017Phys. Rev. Lett.1901701View full textAdd to dashboardCite

Contact Info

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About

Multi-Orbital Molecular Compound (TTM-TTP)I₃: Effective Model and Fragment Decomposition

Dynamical Reduction of the Dimensionality of Exchange Interactions and the “Spin-Liquid” Phase of κ - (BEDT−TTF)2
Powell
¹
,
Kenny
²
,
Merino
³

2017
Phys. Rev. Lett.
19
0
17
0
1
View full text Add to dashboard Cite