Observation of the Berezinskii-Kosterlitz-Thouless transition in Boron-doped diamond films

TL;DR

This study demonstrates the presence of the Berezinskii-Kosterlitz-Thouless transition in boron-doped diamond films, revealing how granularity and vortex dynamics influence superconducting properties and phase transitions.

Contribution

First experimental observation of BKT transition in boron-doped nanocrystalline diamond films with detailed analysis of vortex behavior and phase transition characteristics.

Findings

Robust BKT transition observed in nanocrystalline diamond films

Vortex core energy is anti-correlated with BKT transition temperature

Higher BKT temperature linked to increased vortex-antivortex binding energy

Abstract

The occurrence of the Berezinskii-Kosterlitz-Thouless (BKT) transition is investigated in heavily boron-doped nanocrystalline diamond films through a combination of current-voltage and resistance measurements. We observe a robust BKT transition in the nanocrystalline diamond films with smaller grain size along with transport features related to vortex pinning. The vortex core energy determined through analysis of the resistance temperature curves was found to be anti-correlated to the BKT transition temperatures. It is also observed that the higher BKT temperature is related to an increased vortex-antivortex binding energy derived from the activated transport regions. Further, the magnetic field induced superconductor insulator transition shows the possibility of the charge glass state. The consequences of granularity such as localization and vortex pinning can lead to tuneable BKT temperatures and strongly affects the field induced insulating state.