• Ekimov, Evgeny A.
• Szabó, Pavol
• Vanacken, Johan
• Li, Jun
• Moshchalkov, Victor V.
• Kačmarčík, Jozef
• Cerbu, Dorin
• Samuely, Tomas
• Huang, Junwei
• Pereira, Paulo J.
• Zhang, Gufei

Abstract

<p>Quantum confinement and coherence effects are considered the cause of many specific features for systems which are generally low dimensional, strongly disordered, and/or situated in the vicinity of the metal-insulator transition. Here, we report on the observation of anomalous resistance peak and specific heat peaks superimposed at the superconducting transition of heavily boron-doped polycrystalline bulk diamond, which is a three-dimensional system situated deep on the metallic side of the boron-doping-driven metal-insulator transition in diamond. The anomalous resistance peak and specific heat peaks are interpreted as a result of confinement and coherence effects in the presence of intrinsic and extrinsic granularity. Our data, obtained for superconducting diamond, provide a reference for understanding the superconductivity in other granular disordered systems. Furthermore, our study brings attention to the significant influence of granular disorder on the physical properties of boron-doped diamond, which is considered a promising candidate for electronics applications.</p>

Topics

• impedance spectroscopy
• Boron
• superconductivity
• superconductivity
• specific heat