Novel phase transition in Et2Me2Sb[Pd(dmit)2]2 at 70 K: A possible mechanism based on strong dimerization of two-level molecules

Tamura, Masafumi; Tajima, Akiko; Kato, Reìzo

doi:10.1016/j.synthmet.2005.07.120

Cited by 18 publications

(28 citation statements)

References 12 publications

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“…The changes in the bond lengths at the transition agree with the valence change assumed here [15]. The in-plain arrangement of the charged and neutral dimers coincides with one of the predicted patterns from Madelung calculations [67].…”

Section: A Novel Charge Separation In the Et 2 Me 2 Sb Saltsupporting

confidence: 81%

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Variety of valence bond states formed of frustrated spins on triangular lattices based on a two-level system Pd(dmit)₂

Tamura

Kato

2009

Science and Technology of Advanced Materials

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Recent studies on the physical properties of the triangular system based on the Pd(dmit) 2 salts (dmit = 1,3-dithiole-2-thione-4,5-dithiolate) are reviewed. Quantum chemical architectures of the Pd(dmit) 2 molecule and its dimer are introduced with emphasis on the strong dimerization of a two-level system, which provides unique physical properties of the salts. The magnetic properties are outlined in view of the magneto-structural correlation specific to the frustrated spin systems. Some newly discovered ground states and their origins are discussed, for which the valence bond formation plays a key role. Among them, the two-level structure is crucial for the novel charge-separated state found in two salts. The valence bond ordering, similar to the spin-Peierls transition, has been found in a two-dimensional frustrated spin system. The physical aspects and possible relation to the pressure-induced superconductivity are discussed.

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Section: A Novel Charge Separation In the Et 2 Me 2 Sb Saltsupporting

confidence: 81%

“…(In our earlier study [2], it was argued that the Et 2 Me 2 Sb salt has no phase transition. It turned out later that this is due to the suppression of the phase transition by impurity [67].) Structural changes are involved in these transitions.…”

Section: A Novel Charge Separation In the Et 2 Me 2 Sb Saltmentioning

confidence: 99%

Variety of valence bond states formed of frustrated spins on triangular lattices based on a two-level system Pd(dmit)₂

Tamura

Kato

2009

Science and Technology of Advanced Materials

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“…As mentioned in Section 3.1, the magnetic susceptibility of the Et 2 Me 2 Sb salt shows a sharp transition from the frustrated paramagnetic state to the nonmagnetic state at 70 K. 57 The Et 2 Me 2 Sb salt has an almost regular triangular lattice, and there should be strong frustration effect. The transition in the Et 2 Me 2 Sb salt indicates that the antiferromagnetic ordering is not the only way to remove the frustration and there are another possibilities that are associated with valence bond formation.…”

Section: Interdimer Charge Order (Co) Associated With Homolumo Level mentioning

confidence: 79%

Development of π-Electron Systems Based on [M(dmit)2] (M = Ni and Pd; dmit: 1,3-dithiole-2-thione-4,5-dithiolate) Anion Radicals

Kato¹

2014

Bulletin of the Chemical Society of Japan

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Molecular conductors based on [M(dmit)2] (M = Ni and Pd) present a variety of π electron systems that pave the way for a higher stage of solid-state science. Supramolecular interactions between [Ni(dmit) 2 ] anion and halogen-containing cations provide bilayer systems that are characterized by coexistence of two crystallographically independent anion layers with different molecular arrangements and contrasting (for example, metal/insulator and ferromagnetic/antiferromagnetic) properties. In [Pd(dmit) 2 ] salts in the Mott insulating state, a small energy difference between HOMO and LUMO coupled with strong dimerization affords HOMOLUMO band inversion. The dimer units [Pd(dmit) 2 ] 2 ¹ form a triangular lattice, and interplay of strong electron correlation and spin frustration generates a wide variety of magnetic/charge states including antiferromagnetic long-range order, quantum spin liquid, charge order, and valence bond order, depending on counter cations. The cation dependence is attributed to a systematic arch-shaped molecular distortion that tunes the anisotropy of interdimer transfer integrals. This means that the [Pd(dmit) 2 ] molecular skeleton is sufficiently flexible within the crystal field, and molecular degrees of freedom play an important role in fine tuning of the electronic state.

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“…The CO states accompanied by the tetramers and octamers would be favourable if there were an inversion in the energy levels of the molecular orbitals near the Fermi level ε F 31,35,36,38–40 . As a result of such an inversion, the highest occupied molecular orbitals (HOMOs) and the lowest unoccupied molecular orbitals (LUMOs) of the monomers in Fig.…”

Section: Discussionmentioning

confidence: 99%

Charge and Lattice Fluctuations in Molecule-Based Spin Liquids

Yamamoto

Fujimoto

Naito

et al. 2017

Sci Rep

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Spin liquid (SL) systems have been the subject of much attention recently, as they have been theoretically predicted to not freeze, even at 0 K. Despite extensive searches being made for such a system, only a few candidates have been found. All of these candidates share geometrical frustrations that are based on triangular lattices. We applied vibrational spectroscopy to one of the candidates of a molecule-based SL system, and we compared its results against three antiferromagnetic compounds and four charge-ordered compounds. All of their structural motifs belong to triangular lattices. The C=C stretching modes in the SL state indicated that there were charge and lattice fluctuations. These fluctuations were suppressed but non-negligible in the AF compounds. This finding is potentially significant, as it indicates that a hidden lattice and charge fluctuation are the driving force of a geometrical frustration, which eventually leads to a SL state.

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Novel phase transition in Et2Me2Sb[Pd(dmit)2]2 at 70 K: A possible mechanism based on strong dimerization of two-level molecules

Cited by 18 publications

References 12 publications

Variety of valence bond states formed of frustrated spins on triangular lattices based on a two-level system Pd(dmit)₂

Variety of valence bond states formed of frustrated spins on triangular lattices based on a two-level system Pd(dmit)₂

Development of π-Electron Systems Based on [M(dmit)2] (M = Ni and Pd; dmit: 1,3-dithiole-2-thione-4,5-dithiolate) Anion Radicals

Charge and Lattice Fluctuations in Molecule-Based Spin Liquids

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Novel phase transition in Et2Me2Sb[Pd(dmit)2]2 at 70 K: A possible mechanism based on strong dimerization of two-level molecules

Cited by 18 publications

References 12 publications

Variety of valence bond states formed of frustrated spins on triangular lattices based on a two-level system Pd(dmit)2

Variety of valence bond states formed of frustrated spins on triangular lattices based on a two-level system Pd(dmit)2

Development of π-Electron Systems Based on [M(dmit)2] (M = Ni and Pd; dmit: 1,3-dithiole-2-thione-4,5-dithiolate) Anion Radicals

Charge and Lattice Fluctuations in Molecule-Based Spin Liquids

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Product

Resources

About

Variety of valence bond states formed of frustrated spins on triangular lattices based on a two-level system Pd(dmit)₂

Variety of valence bond states formed of frustrated spins on triangular lattices based on a two-level system Pd(dmit)₂