Bosonic Anomalies in Boron-Doped Polycrystalline Diamond

Anomalous Anisotropy in Superconducting Nanodiamond Films Induced by Crystallite Geometry

“…A network composed of ordered uniform weak links should give rise to the emergence of the characteristic features of the Josephson effect, e.g., zero-bias supercurrent, modulations of the critical current as a function of magnetic field, and oscillations of the magnetic field dependence of resistivity [33], yet no such characteristic features of the Josephson effect have been reported for granular superconducting diamond. However, Josephson-effect-like traits such as current-induced Josephson noise have been observed in nanodiamond films [34], and strong intergrain and intragrain fluctuations of the superconducting order parameter have been reported for superconducting granular diamond by scanning tunneling microscopy/spectroscopy [10,15,18]. The absence of pronounced Josephson effect in nanodiamond films is highly likely owing to the high degree of disorder.…”

“…By decreasing the mean grain size, a systematic reduction of the coherence length was realized in a set of nanodiamond films [14]. When increasing the mean intergrain spacing or the applied pressure, a bosonic insulating state emerged in nanodiamond films as a result of suppressed intergrain Josephson coupling and localized intragrain superconducting order parameter [15][16][17][18].…”

Superconductivity in single-crystalline aluminum- and gallium-hyperdoped germanium

“…The presence of the superconductor-insulator transition clearly reveals the inhomogeneous character of the superconductor. Due to local superconducting regions, even in the insulating state such hyperdoped semiconductors demonstrate nonlinear transport phenomena [22] and anomalous large magnetoresistance [23]. 3 However, for a perfect monolithic integration of superconducting nanocircuits in semiconductor devices, a homogeneous and single-crystalline structure is desirable.…”

Flux pinning and improved critical current density in superconducting boron doped diamond films

“…The work by Willem et al [13] and Zhang et al [14], showed the microscopically inhomogeneous nature of superconductivity in BDD. Importance of spin ordering and disorder have been highlighted by Zhang et al, revealing ferromagnetism [15] and anomalous resistance peak [16,17] in superconducting diamond. Furthermore, the spectroscopic studies that showed existence of hole states near the valence band maximum (VBM) using x-ray absorption spectroscopy (XAS) [18] and the angle resolved photoelectron spectroscopy (ARPES) studies of homoepitaxial BDD films by Yokoya et al which demonstrated merging of the impurity band into valence band in the metallic side of IMT [19].…”