Multiorbital antiferromagnetic metal induced by intramolecular self-doping

Takagi, Ryuzo; Gangi, Hiro; Miyagawa, Kazuya; Nishibori, Eiji; Kasai, Hidetaka; Seo, Hitoshi; Zhou, Biao; Kobayashi, Akiko; Kanoda, K.

doi:10.1103/physrevresearch.2.033321

Cited by 4 publications

(2 citation statements)

References 45 publications

(95 reference statements)

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“…The ratio v F /v F = 0.58 is nearly equal to 4t a /∆E = 0.59 when 4t a = 17 meV, consistently indicating a reduction in the band width. The C iso value is reasonably close to C iso of 126 and 114 ppm, respectively, in [Zn(tmdt) 2 ] and [Au(tmdt) 2 ] with tmdt ligand of common molecular frame to dmdt [25,27]. 1/T 1 T in the DF regimes above T cr is nearly solely determined by v F .…”

supporting

confidence: 60%

NMR verification of Dirac nodal lines in a single-component molecular conductor

Sekine¹,

Sunami²,

Hatamura³

et al. 2022

Preprint

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The Dirac nodal line (DNL) is a novel form of massless Dirac fermions that reside along lines in momentum space. Here, we verify genuine DNLs in the molecular material, [Ni(dmdt)2], with the combined NMR experiments and numerical simulations. The NMR spectral shift and spin-lattice relaxation rate divided by temperature, 1/T1T , decrease linearly and quadratically with temperature, respectively, and become constant at low temperatures, consistent with slightly dispersive DNLs with small Fermi pockets. Comparison of these results with model simulations of DNLs reveals the suppression of the Fermi velocity and the enhancement of antiferromagnetic fluctuations due to electron correlation as well as the influence of the Landau quantization. The present study offers a demonstration to identify the DNL and evaluate the correlation effect with NMR.

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supporting

confidence: 60%

NMR verification of Dirac nodal lines in a single-component molecular conductor

Sekine¹,

Sunami²,

Hatamura³

et al. 2022

Preprint

Self Cite

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“…It should be noted that a lot of purely organic neutral radicals have been designed and synthesized, and some of them have already been utilized as the component of molecular conductors ( i.e. , neutral radical molecular conductors); − however, purely organic neutral radicals with a partially oxidized/reduced state (0 < δ < 1) have never been developed so far. , We expect that such partially oxidized/reduced neutral radicals can form a variety of band-filling states depending on δ; this is in remarkable contrast to the fact that the abovementioned conventional neutral radicals in principle form a half-filled band attributable to the singly occupied molecular orbital (SOMO) …”

Section: Introductionmentioning

confidence: 99%

Partially Oxidized Purely Organic Zwitterionic Neutral Radical Conductor: Multi-step Phase Transitions and Crossover Caused by Intra- and Intermolecular Electronic Interactions

et al. 2022

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Formation of a partially charge-transfer or partially oxidized/reduced state has been one of the most important requirements for the development of highly conducting molecular materials, such as organic metals and superconductors. This requirement has been fulfilled by combining appropriate electron-donor and acceptor molecules to construct multi-component molecular complexes/salts, such as (TTF+0.59)(TCNQ–0.59) and (BEDT-TTF+0.5)2X–, where TTF = tetrathiafulvalene, TCNQ = tetracyanoquinodimethane, BEDT-TTF = bis(ethylenedithio)tetrathiafulvalene, and X = monovalent inorganic anion. Here, we propose a methodology to fulfill this requirement by a single neutral molecule; namely, we have connected two TTF+0.5-type partially oxidized π-skeletons through a boron anion to design a purely organic zwitterionic neutral radical {[(PDT-TTF-Cat) 2 ] + B – } • . This molecule was successfully obtained as air-stable crystals containing solvent tetrahydrofuran (THF) molecules. Measurements of electrical resistivity, magnetic susceptibility, and X-ray diffraction reveal that the partially oxidized state is certainly formed, which enables realization of a 3/4-filled electron band. Furthermore, this system has intramolecular charge degrees of freedom, attributable to the two TTF+0.5 π-skeletons introduced into the molecule. The resulting interplay of intra- and intermolecular charge degrees of freedom (or simply, intra- and intermolecular electronic interactions) has led to multi-step phase transitions and crossover, providing unique strongly correlated electron properties, such as the formation of a three-dimensional charge-ordered dimer-Mott insulating state and its melting triggered by disorder–order transformation of the co-crystallized solvent THF molecules at low temperatures.

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Single-Component Molecular Conductors — Multi-Orbital Correlated π-d Electron Systems

Kobayashi

Zhou

Takagi

et al. 2021

Bulletin of the Chemical Society of Japan

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Traditional molecular conductors are composed of more than two chemical species. Two prerequisites for the design of molecular metals have long been considered to be 1) forming of the electronic band and 2) existence of charge carriers created by the intermolecular charge transfer between the molecules constructing the band and other chemical species. On the other hand, a single-component molecular metal, [Ni(tmdt)2] (tmdt = trimethylenetetrathiafulvalenedithiolate), was developed in 2001; it is a planar nickel complex coordinated by the extended-TTF dithiolate ligands, tmdt from both sides. Since then, various types of single-component molecular conductors with a variety of extended-TTF dithiolate ligands have been developed. In this account, we briefly describe the recent progress in research on single-component molecular conductors. First, single-component molecular conductors in isostructural systems, [M(tmdt)2] (M = Ni, Pd, Pt, Au, and Cu) are described. Recent orbital-selective 13C and 1H NMR experiments have genealogically elucidated the differences in the electronic states and physical properties of these systems, that is, their various unusual phenomena are produced from their multi-orbital correlated π or π-d electron systems. Next, we describe [Ni(hfdt)2] (hfdt = bis(trifluoromethyl)tetrathiafulvalenedithiolate), the first single-component molecular superconductor, which was revealed by high-pressure resistivity measurements with a diamond anvil cell (DAC). The superconducting transition occurred around 7.5–8.7 GPa with a maximum Tc (onset temperature) of 5.5 K. Recent theoretical calculation has revealed that [Ni(hfdt)2] will be a new molecular Dirac electron system. In the final section, we briefly introduce molecular Dirac electron systems. Recently, a new series of semimetals, [M(dmdt)2] (M = Pt and Ni; dmdt = dimethyltetrathiafulvalenedithiolate) was synthesized. They belong to a three-dimensional ambient-pressure molecular massless Dirac electron system. The first-principles band structure calculations of [M(dmdt)2] (M = Pt and Ni) revealed that Dirac cones emerge along the a* direction and form Dirac nodal lines.

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Multiorbital antiferromagnetic metal induced by intramolecular self-doping

Cited by 4 publications

References 45 publications

NMR verification of Dirac nodal lines in a single-component molecular conductor

NMR verification of Dirac nodal lines in a single-component molecular conductor

Partially Oxidized Purely Organic Zwitterionic Neutral Radical Conductor: Multi-step Phase Transitions and Crossover Caused by Intra- and Intermolecular Electronic Interactions

Single-Component Molecular Conductors — Multi-Orbital Correlated π-d Electron Systems

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