Effects of Rashba-spin–orbit coupling on superconducting boron-doped nanocrystalline diamond films: evidence of interfacial triplet superconductivity

Abstract

Among the many remarkable properties of diamond, the ability to superconduct when heavily doped with boron has attracted much interest in the carbon community. When considering the nanocrystalline boron doped system, the reduced dimensionality and confinement effects have led to several intriguing observations most notably, signatures of a mixed superconducting phase. Here we present ultra-high-resolution transmission electron microscopy imaging of the grain boundary and demonstrate how the complex microstructure leads to enhanced carrier correlations. We observe hallmark features of spin–orbit coupling (SOC) manifested as the weak anti-localization effect. The enhanced SOC is believed to result from a combination of inversion symmetry breaking at the grain boundary interfaces along with antisymmetric confinement potential between grains, inducing a Rashba-type SOC. From a pronounced zero bias peak in the differential conductance, we demonstrate signatures of a triplet component believed to result from spin mixing caused by tunneling of singlet Cooper pairs through such Rashba-SOC grain boundary junctions.

Demonstration of the Holonomically Controlled Non-Abelian Geometric Phase in a Three-Qubit System of a Nitrogen Vacancy Center

“…At the zero frequency, P r has a peak at the origin or zero detune time (like the weak localization phenomena observed in the magnetic field-dependent resistance of metal with the effect of RSOC). This becomes a minimum by the application of the Rabi frequency which is like weak anti-localization [ 31 ]. This is a hallmark feature of RSOC in a topologically protected material.…”

“…A three-qubit system produces a similar effect to Rashba spin–orbit coupling (RSOC) and vortex structures in materials which are highlighted in the paper [ 26 , 27 , 28 ]. There have been attempts to acquire the geometric phase in a qubit circuit of IBM QE [ 21 , 29 , 30 , 31 ]. P r shown in Figure 1 b–e is defined as the probability of the desired state (most often, the initial state) after measurement.…”

Diaphite: diamond-graphene hybrid nanostructures grown in CH4/H2/N2 chemistry

“…This finding hints at the potential for superconductivity and superparamagnetism 22 . Additionally, research has shown that an interfacial grain boundary network in boron-doped nanocrystalline diamond films induces strong localized spin-orbit coupling, which results in conduction occurring in a triplet state 23 . Overall, the precise regulation of doping and control over the formation of mixed-phase defects in nanocrystalline diamond structures have garnered significant interest in recent years.…”