Superconductivity in zero-dimensional indium nanoparticles

Abstract

An In nanoparticle powder was fabricated by employing the thermal evaporation method. Size analysis using x-ray diffraction profiles analysis and atomic force microscopy images indicates an average particle diameter of 36(2)nm and a Gaussian size distribution with a half-width of 3nm. The superconducting critical temperature of the In nanopowder increases slightly to 3.57(3)K, which was found to be extremely insensitive to the applied magnetic field. The critical magnetic field reaches ∼5T, which is a factor of 170 times higher than that of bulk In.

Reflectionless Tunneling at the Interface between Nanoparticles and Superconductors

“…Most thermally deposited films exhibited ZFCP widths <0:5 T, and only for the thinnest films (&20 nm) were they >1 T [27]. Disordered superconducting systems are known to exhibit enhanced H c [29,30]. Since S contacts the highly disordered NPF, S in turn may be disordered near the interface, leading to similarly enhanced H c and broad ZFCPs [13,31].…”

Facile synthesis of superconducting NbN nanoparticles

“…The superconducting transition temperature T c of the nanoparticles as a function of their size d has been studied both theoretically and experimentally. The reduction of the particle's size d could lead to dramatic changes of the physical behavior of superconductors, such as a reduction on the critical temperature and/or superconducting state of nanosized superconductors [7,20,22]. The possible origin for the slight reduction of superconducting transition temperature is that this is an effect of increased surface area, which may enhance surface electron-phonon scattering effect and compensate the size effect of reducing superconducting transition temperature [18,19].…”

“…Various abnormal phenomena, such as magic effects, quantum size effects, surface effects, hyperfine structure etc., in the nanoparticles, alter the physical behavior of materials [6]. It is known that the superconducting parameters of zerodimensional nanoparticles can be dramatically different from those of bulk materials [7]. Apparently, the most noticeable finite size effect on superconductivity is the loss of superconductivity, when the electron level separation near the Fermi level becomes comparable to the BCS superconducting gap [8].…”

Clean superconducting In nanowires encapsulated within insulating ZnS nanotubes

“…This value is much larger than the bulk penetration depth ͑25 nm as determined by ultrasonic attenuation measurements 20 ͒ and the penetration depth reported for In nanoparticles ͑3.3 nm͒. 21 Therefore, since our nanowires are clean, it would be rational to expect that the penetration depth of the nanowires would be in between these two values, and we may consider 39 nm as the upper limit of the penetration depth for the In nanowires. 22,23 Taking the corresponding to be 89 nm at absolute zero, as obtained from the BCS analysis of our data, the upper limit of the value for the encapsulated nanowires is found to be 0.438, which is much below the critical value.…”