Evidence for an Antiferromagnetic Transition in a Zeolite-Supported Cubic Lattice of<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi mathvariant="italic">F</mml:mi></mml:math>Centers

Srdanov, V. I.; Stucky, Galen D.; Lippmaa, É.; Engelhardt, G.

doi:10.1103/physrevlett.80.2449

Cited by 138 publications

(82 citation statements)

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“…Shared 6Rs are rather narrow, but a large kinetic energy is expected for the s-electron, because of a narrow inside diameter of β-cage, ≈7 Å. These lead to the system of a large U with a finite S. According to the t-U-S-n model, a robust Mott-insulating phase is expected at n ≈ 1 when U > 2B and U > S. Actually, an antiferromagnetism has been clearly observed in Na/Na 3 -SOD below the Néel temperature ≈50 K [9,16]. In K/K 3 -SOD and Rb/K 3 -SOD, much higher Néel temperatures have been observed at 70 and 80 K, respectively [14,34,35].…”

Section: Alkali Metals In Other Zeolitesmentioning

confidence: 99%

“…A new paradigm of electronic system can be provided by the alkali-metal loading into zeolites. Up to now, comprehensive researches have been carried out , especially on magnetic properties [1,2,9,11,[13][14][15][16][17][18][23][24][25][26][27][28][29][30][31][34][35][36][37]39,41,[43][44][45][46]48,50,51], optical properties [1,3,7,24,38,49,53], electrical properties [42,43,49,50,52,53], structural analyses [8,12,22,47] and theoretical calculations …”

Section: Introductionmentioning

confidence: 99%

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Electrons of alkali metals in regular nanospaces of zeolites

Nakano

Nozue

2017

Advances in Physics: X

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The s-electrons of alkali metals loaded into regular nanospaces (nanocages) of zeolite crystals display novel electronic properties, such as a ferrimagnetism, a ferromagnetism, an antiferromagnetism, an insulator-to-metal transition, etc., depending on the kind of alkali metals, their loading density, and the structure type of zeolite frameworks. These properties are entirely different from those in bulk alkali metals of freeelectrons. Alkali-metal clusters are stabilized in cages of zeolites, and new quantum states of s-electrons, such as 1s, 1p, and 1d states in the spherical quantum-well model, are formed. An electron correlation, a polaron effect, and an orbital degeneracy in the quantum states of s-electrons play critical roles in taking on the novel electronic properties. Electronic properties can be overviewed systematically by a coarse-grained model of localized s-electron states in cages based on the tightbinding approximation, followed by the t-U-S-n diagram of the correlated polaron system given by the so-called HolsteinHubbard Hamiltonian: an electron transfer energy through windows of cages (t), a Coulomb repulsion energy between two s-electrons in the same cage (U), a short-range electron-phonon interaction energy due to the cation displacements (S), and an average number of s-electrons per cage (n). Beyond the jellium background model of alkali-metal clusters, a huge spin-orbit interaction has been observed in the 1p degenerate orbitals of clusters, similarly to the Rashba mechanism. ARTICLE HISTORY

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Section: Alkali Metals In Other Zeolitesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Electrons of alkali metals in regular nanospaces of zeolites

Nakano

Nozue

2017

Advances in Physics: X

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“…Generally, the scattering vector q dependence of the magnetic form factor, f m (q), is obtained from the Fourier transform of the electronic-spin-density distribution of a single magnetic site, i. e., f m (q) = ∫ |ψ ↑ (r)| 2 exp(iq · r)dr. Therefore, the quicker reduction in f m (q) of K/K 3 -SOD indicates that the size of the s-electron wave function responsible for the magnetic moment is larger in K/K 3 -SOD than that in Na/Na 3 heavier alkali-metal clusters show higher T N 's in sodalite. The size and the spatial distribution of the s-electron wave function in the cluster has been expected to increase with the size of the alkali cations while the β cage is a rather rigid structural unit.…”

Section: Resultsmentioning

confidence: 98%

“…Then, an unpaired s electron provided 1 by the guest atom is shared by four Na + ions and is confined in the cage. Srdanov and his coworkers found the AFM ordering below the Néel temperature T N of 48 K when they made the Na 3+ 4 clusters in almost all the β cages [3]. It was confirmed directly by neutron diffraction (ND) that the s-electron spins in the body centers are aligned antiparallel to those in the corners in the bcc lattice [8].…”

Section: Introductionmentioning

confidence: 94%

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Neutron Diffraction Study of Antiferromagnetic Potassium Nanoclusters Incorporated into Sodalite

Nakano

Matsuura

Hanazawa

et al. 2015

Proceedings of the 2nd International Symposium on Science at J-Parc — Unlocking the Mysteries of Life, Matter and the Universe

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We have performed a neutron diffraction study on potassium clusters formed in a regular nanospace of sodalite, a kind of aluminosilicate zeolites. This material is known to show an antiferromagnetic ordering below the Néel temperature T N of 72 K. We have observed the 001 magnetic Bragg peak at low temperature indicating a long-range magnetic ordering. By the analysis of the intensity ratio of the magnetic Bragg peak to the nuclear one, the product of the ordered magnetic moment and the form factor, µ · f m , is examined. The value is found to be significantly smaller than that in sodium clusters. This is caused by the quicker decrease in f m as a function of the magnitude of the scattering vector q, namely, the larger size of s-electron wave function in potassium cluster. The higher T N in potassium clusters probably originates from the larger size of the wave function because that enhances the kinetic exchange coupling between adjacent clusters.

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„Supramolekulare“ Festkörperchemie: einander durchdringende diamantartige Gerüststrukturen mit U4+-Ionen und zweizähnigen molekularen P2S62−-S,S′-„Stäben“ in UP4S12

et al. 2001

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Organische Verbindungen können sich bei tiefen Temperaturen zu organisierten Aggregaten anordnen, die zu molekularer Erkennung fähig sind und als biomimetische Systeme dienen können. [1] Dies führte in der supramolekularen organische Chemie zu erstaunlichen Ergebnissen, [2] unter anderem zur Bildung dreidimensionaler (3D-) Netzstrukturen vom Super-Diamant- [3] und Super-Wurtzit-Typ, [4] die durch Wasserstoffbrückenbindungen stabilisiert werden. Im Bereich der anorganischen Koordinationschemie schlugen Hoskins und Robson [5] eine Strategie zur Synthese neuer 3D-Verbindungen vor, die Gerüststrukturen aufweisen und aus geeigneten Metallzentren (z. B. mit tetraedrischer, quadratischplanarer oder oktaedrischer Konnektivität) sowie stab-oder plattenförmigen molekularen Baueinheiten unterschiedlicher Natur und Länge aufgebaut werden. Dieses Grundprinzip wurde in den vergangenen Jahren erfolgreich zur Synthese neuer Verbindungen angewendet, deren Strukturen aus miteinander verflochtenen Netzen bestehen. [6±8] Jeder Grundtyp der anorganischen Strukturchemie (z. B. Diamant, PtS, a-Polonium) kann als Prototyp für eine ganze Familie neuer Netze betrachtet werden, in denen Bindungen der Stamm-struktur durch eine Reihe molekularer Stäbe ersetzt sind. Einfache zweizähnige lineare Liganden unterschiedlichen Durchmessers dienen als stabartige Verbindungselemente. [9] In manchen Fällen entstehen diese polymeren Strukturen als polymere Netze mit groûen Hohlräumen und/oder Kanälen, in anderen, wie Zn(CN) 2 , [10] werden die Hohlräume mit einem oder mehreren identischen unabhängigen Netzen gefüllt. ¾hnliche präparative Erfolge sind bisher bei Festkörperreaktionen auf sehr wenige Beispiele wie [Ph 4 P] 2 [M(Se 6 ) 2 ], [11] K 2 PdSe 10[12] oder Ta 4 P 4 S 29 [13] beschränkt. Ausgehend von der Beobachtung, dass PS 4 -und P 2 S 6 -Gruppen in Thiophosphaten der elektronenarmen Übergangsmetalle [14] als ein-, zwei-oder dreizähnige Liganden fungieren können, und der Tatsache, dass selbst hohe Koordinationszahlen von Metallen wie Niob oder Uran mit Chelatliganden zu niedrigen Verknüpfungsgraden führen können, suchten wir im quasibinären System US 2 /P 2 S 5 nach neuen Verbindungen, in denen das Uranzentrum von PS 4 -, P 2 S 6 -oder S 3 P(S) x PS 3 -Gruppen koordiniert ist. Wir berichten hier über die Synthese und die strukturelle Charakterisierung von U(P 2 S 6 ) 2 1, einer Verbindung mit dreidimensionalem Aufbau, die aus drei einander durchdringenden SiO 2 -analogen Netzen besteht. Die erweiterte Struktur kann ausgehend von der Länge der verbindenden P 2 S 6 -Stäbe erklärt werden.

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Evidence for an Antiferromagnetic Transition in a Zeolite-Supported Cubic Lattice ofFCenters

Cited by 138 publications

References 20 publications

Electrons of alkali metals in regular nanospaces of zeolites

Electrons of alkali metals in regular nanospaces of zeolites

Neutron Diffraction Study of Antiferromagnetic Potassium Nanoclusters Incorporated into Sodalite

„Supramolekulare“ Festkörperchemie: einander durchdringende diamantartige Gerüststrukturen mit U4+-Ionen und zweizähnigen molekularen P2S62−-S,S′-„Stäben“ in UP4S12

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