NMR measurement of superconducting-state spin susceptibility in alkali fullerides

Va, Stenger; Recchia, Charles H; Vance, Jessica Ainsworth; Pennington, C. H.; Dr, Buffinger; Rp, Ziebarth

doi:10.1103/physrevb.48.9942

Cited by 25 publications

(15 citation statements)

References 19 publications

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“…Such a linear temperature dependence of the shift has already been observed in the NMR of various alkali in fullerides 30,31,32 . Its origin is not well understood, but as it is not related to the electronic susceptibility 30 , it is probably of orbital origin and we will include this linear variation in the chemical shift σ.…”

Section: Bsupporting

confidence: 63%

Persistence of molecular excitations in metallic fullerides and their role in a possible metal to insulator transition at high temperatures

et al. 2002

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We present 13 C NMR spin-lattice relaxation measurements (1/T1) in Na2CsC60 and Rb3C60 from 10 to 700 K. The large temperature range of this measurement allow to define unambiguously an increase of 1/T1T with increasing temperature, which is anomalous in a simple metallic picture, where the Korringa law predicts 1/T1T = cst. We attribute this increase to the existence of an additional relaxation channel related to singlet-triplet (ST) excitations of Jahn-Teller distorted C 2− 60and C 4− 60 . These units are formed within the metal on very short time scales (10 −14 sec) that do not imply static charge segregation. We show that the amplitude of the ST component depends directly on the density of states, which indicates an interplay between metallic and molecular excitations. Such an interaction is also revealed by the high temperature behavior of Na2CsC60 and CsC60, that we then discuss. A divergence between the behaviors of 1/T1, the NMR shift and the ESR susceptibility is interpreted as the result of a rapid increase of the lifetime of the charge carriers, signaling a tendency to charge localization. In our analysis, the particular stability of C 2n− 60 is then a common feature of all known metallic fullerides and allow to reconcile apparently contradicting properties of these systems.

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Section: Bsupporting

confidence: 63%

Persistence of molecular excitations in metallic fullerides and their role in a possible metal to insulator transition at high temperatures

et al. 2002

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“…In K 2RbC60 the larger Rb ions occupy the large octahedral sites whereas in Rb 2CsC60 the Rb ions are smaller and therefore pushed on the smaller tetrahedral sites. Site preferential order in ternary fullerene compounds of the same nominal stoichiometry was found earlier also by means of X-ray techniques [16,17] as well as NMR [9,12]. Considering the different prepara- tion methods described in [12,16], and in this work it is noticeable that the formation of site ordered fullerides is relatively insensitive to the route of sample preparation.…”

Section: Resultsmentioning

confidence: 55%

“…For all samples investigated here, the 87Rb NMR spectra generally show the typical characteristics found in other laboratories for samples of the same nominal composition [7][8][9][10][11][12][13], namely the T f line and the site preferential order in the ternary compounds. A more detailed analysis of our 87Rb NMR spectra reveals two special features: an additional broad line in all samples (Fig.…”

Section: Discussionmentioning

confidence: 74%

“…In contrast to the BC MAS NMR spectra the three 87Rb NMR spectra exhibit no differences, i.e., within the margin of noise the spectra are identical. They show the characteristic three lines (T, T ', 0) reported also by other groups [7][8][9][10][11][12][13]. We want to add here that the comparison between 85Rb and 87Rb NMR on Rb 3C60 proved the magnetic origin of the line shifts [11] and that the different paramagnetic shifts of the Rb signals are due to lattice site dependent hyperfine couplings [7,8].…”

Section: Methodsmentioning

confidence: 71%

“…13C NMR as an important technique to reveal structural and dynamical information in organic solids has also been successfully used in the characterization of alkali metal intercalated C 60 [3-6] so far. Besides the 13C NMR the alkali nuclei were measured, and in particular 87Rb NMR results have been reported by some authors [7][8][9][10][11][12][13]. They found narrow and well resolved lines corresponding to the tetrahedral (T) and octahedral (0) sites in the fcc lattice of the alkali metal intercalated A)33-xC6o compounds.…”

Section: Introductionmentioning

confidence: 99%

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87Rb NMR investigations on binary and ternary fullerene compounds: Rb3C60, K2RbC60 and Rb2CsC60

et al. 1996

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Results of l3C MAS NMR and 87Rb NMR measurements on Rb 3C60 , K 2RbC60 and Rb 2CsC60 are presented. The 87Rb NMR spectra show generally the same characteristics as already reported by other authors. For the ternary compound the degree of site preferential order of the alkali metal ions agrees with the analysis of X-ray absorption data. Furthermore, in the roomtemperature 87Rb NMR spectra of all samples an additional broadened line is detected indicating that at least for the samples prepared from sublimed C 60 a considerable amount of the Rb ions is located on sites with symmetry lower than cubic.

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Organic quantum materials: A review

Wang

Zhang

2023

SmartMat

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Interests in organic quantum materials (OQMs) have been explosively growing in the field of condensed physics of matter due to their rich chemistry and unique quantum properties. They are strongly correlated systems and show novel electromagnetic performance such as high‐temperature superconducting, quantum sensing, spin electronics, quantum dots, topological insulating, quantum Hall effects, spin liquids, qubits, and so forth, which exhibit promising prospects in information communication and thus facilitate the construction of a modern intelligent society. This article reviews recent developments in the research on the electromagnetic characteristics of OQMs. We mainly give an overview on the progress of superconductors and quantum spin liquids based on organic materials and describe their possible mechanisms. Numerous experimental findings exhibit new exciton interactions and provide insights into exotic electronic properties. Finally, their association and strategies for realizing multiple quantum states in one system are discussed.

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NMR measurement of superconducting-state spin susceptibility in alkali fullerides

Cited by 25 publications

References 19 publications

Persistence of molecular excitations in metallic fullerides and their role in a possible metal to insulator transition at high temperatures

Persistence of molecular excitations in metallic fullerides and their role in a possible metal to insulator transition at high temperatures

87Rb NMR investigations on binary and ternary fullerene compounds: Rb3C60, K2RbC60 and Rb2CsC60

Organic quantum materials: A review

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