Spin gap evolution upon Ca doping in the spin ladder series $Sr_{14-x}Ca_xCu_{24}O_{41}$ by inelastic neutron scattering
| Autor: | Deng, Guochu, Tsyrulin, N., Bourges, P., Lamago, D., Ronnow, H., Kenzelmann, M., Danilkin, S., Pomjakushina, E., Conder, K. |
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| Rok vydání: | 2013 |
| Předmět: | |
| Zdroj: | Phys. Rev. B 88, 014504 (2013) |
| Druh dokumentu: | Working Paper |
| DOI: | 10.1103/PhysRevB.88.014504 |
| Popis: | The spin gap evolution upon Ca doping in Sr14-xCaxCu24O41 was systematically investigated using inelastic neutron scattering. We discover that the singlet-triplet spin gap excitation survives in this series with x up to 13, indicating the singlet dimer ground state in these compounds. This observation corrects the previous speculation that the spin gap collapses at x~13 by the NMR technique. The strong intensity modulation along QH in x=0 gradually evolves into a Q-independent feature in x>11. This could be attributed to the localized Cu moment magnetism developing into an itinerant magnetism with increasing x. It is a surprise that the spin gap persists in the normal state of this spin ladder system with metallic behaviour, which evidences the possibility of magnetically-mediated carrier pairing mechanism in a two-leg spin ladder lattice. Comment: 17 pages, 6 figures |
| Databáze: | arXiv |
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