Low Temperature X-Ray and ESR study of one-dimensional compound (TTM-TTP)I3

Fujimura, Naoyuki; Namba, Akihiro; Kambe, Takashi; Nogami, Yasuyuki; Oshima, K.; Mori, Takehiko; Kawamoto, Tadashi; Misaki, Yohji; Yamabe, Tokio

doi:10.1016/s0379-6779(98)00473-1

Cited by 22 publications

(20 citation statements)

References 3 publications

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“…On the basis of this finding, we infer that the non-magnetic insulating behavior observed at low temperatures in (TTM-TTP)I 3 (Refs. [31][32][33][34] can be attributed to the spin-singlet formation on the t with twofold periodicity along the stacking direction. Incidentally, we observe that the IAF state is almost degenerate with the ICO state, with the energy differences per molecule E IAF − E ICO ≈ 0.15 eV, E SDW − E ICO ≈ 0.30 eV, and E CDW − E ICO ≈ 1.19 eV.…”

Section: Full Fragment Decompositionmentioning

confidence: 99%

“…29,30 In this compound, the non-magnetic insulating behavior at low temperature has been confirmed. [31][32][33][34] A charge ordering reflected by the alternation of valence of TTM-TTP molecule along the stacking direction has been proposed initially. 33,34 The experimental analysis based on Raman-scattering [35][36][37] and x-ray 38 measurements suggested a new type of charge-ordered state, "intra-molecular charge ordering (ICO)," which cannot be described by the conventional single-orbital approximation.…”

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confidence: 99%

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Ab initio derivation of multi-orbital extended Hubbard model for molecular crystals

Tsuchiizu

Omori

Suzumura

et al. 2012

The Journal of Chemical Physics

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From configuration interaction (CI) ab initio calculations, we derive an effective two-orbital extended Hubbard model based on the gerade (g) and ungerade (u) molecular orbitals (MOs) of the chargetransfer molecular conductor (TTM-TTP)I-3 and the single-component molecular conductor Au(tmdt)(2)]. First, by focusing on the isolated molecule, we determine the parameters for the model Hamiltonian so as to reproduce the CI Hamiltonian matrix. Next, we extend the analysis to two neighboring molecule pairs in the crystal and we perform similar calculations to evaluate the intermolecular interactions. From the resulting tight-binding parameters, we analyze the band structure to confirm that two bands overlap and mix in together, supporting the multi-band feature. Furthermore, using a fragment decomposition, we derive the effective model based on the fragment MOs and show that the staking TTM-TTP molecules can be described by the zig-zag two-leg ladder with the inter-molecular transfer integral being larger than the intra-fragment transfer integral within the molecule. The inter-site interactions between the fragments follow a Coulomb law, supporting the fragment decomposition strategy. . First, by focusing on the isolated molecule, we determine the parameters for the model Hamiltonian so as to reproduce the CI Hamiltonian matrix. Next, we extend the analysis to two neighboring molecule pairs in the crystal and we perform similar calculations to evaluate the intermolecular interactions. From the resulting tight-binding parameters, we analyze the band structure to confirm that two bands overlap and mix in together, supporting the multi-band feature. Furthermore, using a fragment decomposition, we derive the effective model based on the fragment MOs and show that the staking TTM-TTP molecules can be described by the zig-zag two-leg ladder with the inter-molecular transfer integral being larger than the intra-fragment transfer integral within the molecule. The inter-site interactions between the fragments follow a Coulomb law, supporting the fragment decomposition strategy.

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Section: Full Fragment Decompositionmentioning

confidence: 99%

mentioning

confidence: 99%

Ab initio derivation of multi-orbital extended Hubbard model for molecular crystals

Tsuchiizu

Omori

Suzumura

et al. 2012

The Journal of Chemical Physics

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“…A tight-binding band calculation suggests that (TTM-TTP)I 3 has a large bandwidth of W = 1 eV. The nature of the insulating state of (TTM-TTP)I 3 has been investigated, but has not get been elucidated [76][77][78][79][80][81]. On the other hand, (TTM-TTP)(I 3 ) 5/3 also has uniform donor stacks similar to (TTM-TTP)I 3 , and it exhibits metallic conductivity down to T MI = 20 K (see also figure 17).…”

Section: (Ttm-ttp)a Xmentioning

confidence: 99%

Tetrathiapentalene-based organic conductors

Misaki

2009

Science and Technology of Advanced Materials

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The synthesis, structure and properties of tetrathiapentalene-based (TTP) organic conductors are reviewed. Among various TTP-type donors, bis-fused tetrathiafulvalene, 2,5-bis(1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene (BDT-TTP) and its derivatives afford many metallic radical cation salts stable down to low temperatures, regardless of the size and shape of the counter anions. Most BDT-TTP conductors have a β-type donor arrangement with almost uniform stacks. Introduction of appropriate substituents results in molecular packing that differs from the β-type. A vinylogous TTP, 2-(1,3-dithiol-2-ylidene)-5-(2-ethanediylidene-1,3-dithiole)-1,3,4,6-tetrathiapentalene (DTEDT) has yielded an organic superconductor (DTEDT) 3 Au(CN) 2 as well as metallic radical cation salts, regardless of the counter anions. (Thio)pyran analogs of TTP, namely (T)PDT-TTP and its derivatives produce molecular conductors with novel molecular arrangements. A TTP analog with reduced π-electron system 2,5-bis(1,3-dithian-2-ylidene)-1,3,4,6-tetrathiapentalene (BDA-TTP) has afforded several organic superconductors. Highly conducting molecular metals with unusual oxidation states (+1, +5/3 and neutral) have been developed on the basis of 2,5-bis(1,3-dithiol-2-ylidene)-1,3,4,6-tetrathiapentalene (BDT-TTP) derivatives and analogous metal derivatives M(dt) 2 (M = Ni, Au).

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“…[5][6][7][8] Theoretical approaches that focus on a single highest-occupied-molecular orbital ͑HOMO͒ or lowest-unoccupied-molecular orbital ͑LUMO͒ have been successful in describing fascinating electronic ordered phase. The magnetic susceptibility 17,18 and NMR measurements 19,20 revealed phase transitions at finite temperature. 2 Nevertheless, new types of molecular solids have been recently synthesized, for instance, aiming at the metallization of the single-component molecular solid family M͑tmdt͒ 2 ͑M =Ni,Au͒, 9 where tmdt stands for trimethylenetetrathiafulvalenedithiolate.…”

Section: Introductionmentioning

confidence: 98%

Intramolecular charge ordering in the multi molecular orbital system (TTM-TTP)I3

Bonnet

Robert

Tsuchiizu

et al. 2010

The Journal of Chemical Physics

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Starting from the structure of the (TTM-TTP)I(3) molecular-based material, we examine the characteristics of frontier molecular orbitals using ab initio (CASSCF/CASPT2) configurations interaction calculations. It is shown that the singly occupied and second-highest-occupied molecular orbitals are close to each other, i.e., this compound should be regarded as a two-orbital system. By dividing virtually the [TTM-TTP] molecule into three fragments, an effective model is constructed to rationalize the origin of this picture. In order to investigate the low-temperature, symmetry breaking experimentally observed in the crystal, the electronic distribution in a pair of [TTM-TTP] molecules is analyzed from CASPT2 calculations. Our inspection supports and explains the speculated intramolecular charge ordering which is likely to give rise to low-energy magnetic properties.

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Low Temperature X-Ray and ESR study of one-dimensional compound (TTM-TTP)I3

Cited by 22 publications

References 3 publications

Ab initio derivation of multi-orbital extended Hubbard model for molecular crystals

Ab initio derivation of multi-orbital extended Hubbard model for molecular crystals

Tetrathiapentalene-based organic conductors

Intramolecular charge ordering in the multi molecular orbital system (TTM-TTP)I3

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