Single grains? M图140 Al302.6400.19 0.20 1110031 hn3711100.36 Abeles, Cohen, Cullen, Phys. Rev. Lett., 17, 632(1966) Crow, Parks, Douglass, Jensen, Giaver, Zeller A.M. Goldman Dynes, Tinkham
Abeles, Cohen, Cullen, Phys. Rev. Lett., 17, 632 (1966) A.M. Goldman, Dynes, Tinkham… Single grains? Crow, Parks, Douglass, Jensen, Giaver, Zeller
△~8 Ralph, Black, Tinkham, Superconductivity in si ingle Metal Particles PRL74,3241-3244(1995) Supercon ductivity? 1959 A」eeoe Yes, superconductivity AWSi3nNe Isolated grain? 人gae Odd-even effects Al electrode Al particle +V2 <H 10 nm size scale Rediscovery of Richardsons equations No yet quantitative
Odd-even effects ~ Supercon ductivity? Isolated grain? Yes, superconductivity 1959 Ralph, Black,Tinkham, Superconductivity in Single Metal Particles PRL 74, 3241-3244 (1995). Rediscovery of Richardson’s equations No yet quantitative
nature materials LETTERS PUBLISHED ONLINE: 30 MAY 2010 DOl: 10.1038/NMAT2768 Observation of shell effects in superconducting nanoparticles of Sn Sangita Bose*, Antonio M. Garcia-Garcia * Miguel M. Ugeda 3, Juan D. Urbina Christian H. Michaelis Ivan Brihuega 3* and Klaus Kern'5 7nm a h=09R Sn nanoparticles Expt data ▲ Pb nanoparticles 0UoN=Eoz △2 1015202530 Particle height(nm Particle height (nm
Å 33 . 5 Å 00 . 0 5.33 Å 0.00 Å 0 nm 7 nm
BCS superconductivity Finite size effects 2 ED v(e) de h,6 levels g E D √△2+ Cis(e-ai V→∞ V finite region (tEp △~Ene1 △=? Shell effects Level Degeneracy Parmenter, Phys. Rev. 166,L-5nm 20T 392(1967)
BCS superconductivity Finite size effects V → Δ~ De -1/ V finite Δ=? Shell Effects Parmenter, Phys. Rev. 166, 392 (1967) L ~ 5nm Level Degeneracy 20Tc !
△>>8 Grains h.level Heiselberg(2002): harmonic potentials, cold atom Kresin, Ovchinnikov, boyaci (2007): Spherical, too high Tc Peeters, et al,(2005-): BCS, Sn BaG in a wire, cvlinder 1.3 1.2 Devreese(2006): Richardson equations in a box 0.9 Olofsson(2008 ): Estimation 08 17.217417.617.818.018.2 of fluctuations in BCs 0(nm)
>> Heiselberg (2002): harmonic potentials, cold atom Kresin, Ovchinnikov, Boyaci (2007) : Spherical, too high Tc Peeters, et al, (2005-): BCS, BdG in a wire, cylinder.. Olofsson (2008): Estimation of fluctuations in BCS Devreese (2006): Richardson equations in a box Grains