Superconductivity in Li-doped α-rhombohedral boron
T. Nagatochi, H. Hyodo, A. Sumiyoshi, K. Soga, Y. Sato, M. Terauchi, F. Esaka, K. Kimura
DOI 10.1103/PhysRevB.83.184507 · Physical Review B
Active bibliographic source — not scientific approval
Bibliographic access preserves source history; it does not approve extracted materials or validate reported claims. Review warnings on each occurrence separately.
Abstract
Metal transition and superconductivity were observed in Li-doped α-rhombohedral boron (α-B12). The authors have established a purification method and obtained a large amount of high-purity α-B12 powder. Li doping into purified α-B12 was attempted by vapor diffusion processing (VDP) in a Mo or Ta tube. Li-doped α-B12 contained metallic glittering particles. Meissner effects were observed in such a compound with the nominal composition LixB12 (x = 1.0, 1.4, 1.5, 1.7, or 2.5) (Tc = 3.2–7 K). As for Li2.5B12, the temperature dependence of its electrical conductivity indicates a metallic character and its electrical resistivity drop is detected near the Meissner temperature. The existence of Li and Fermi edges in Li-doped α-B12 crystals was verified by transmission electron microscopy-electron energy loss spectroscopy (TEM-EELS). Lattice expansion, which is a well-known indicator of metal doping into a crystal, was also observed. Thus, Li doping into α-B12 was successfully achieved. Our work also suggests that it is possible to dope a larger amount of Li into α-B12 and to increase its Tc.
Source-reported materials — not catalogue approval
| Formula | Reported Tc (K) | Pressure (GPa) | Type |
|---|---|---|---|
| Li1.0B12 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | 3.24 | Pressure not reported | onset |
| Li1.4B12 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | 3.2 | Pressure not reported | onset |
| Li1.4B12 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | 3.8 | Pressure not reported | onset |
| Li1.5B12 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | 4 | Pressure not reported | onset |
| Li1.5B12 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | 5.6 | Pressure not reported | onset |
| Li1.7B12 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | 7.05 | Pressure not reported | onset |
| Li2.5B12 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | 3.19 | Pressure not reported | onset |
| Li2.5B12 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | 5.21 | Pressure not reported | onset |
| Li2.5B12 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | 7.02 | Pressure not reported | onset |
| Li2.5B12 Archive — visibility unverified Source-occurrence policy only; no material identity or catalogue acceptance is inferred from the formula. | 6.62 | Pressure not reported | onset |