Subkelvin tunneling spectroscopy showing Bardeen-Cooper-Schrieffer superconductivity in heavily boron-doped silicon epilayers

Franck Dahlem , Thierry Kociniewski (1) , C. Marcenat (2) , Audrey Grockowiak (3) , Laëtitia Pascal (4) , Philipp Achatz (5) , J. Boulmer (6) , D. Debarre (6) , Thierry Klein (3) , Etienne Bustarret (5) , Hervé Courtois (4)

1 GEMAC - Groupe d'Etude de la Matière Condensée
2 LaTEQS - Laboratoire de Transport Electronique Quantique et Supraconductivité
3 NEEL - MagSup - Magnétisme et Supraconductivité
4 NEEL - QuNES - Nano-Electronique Quantique et Spectroscopie
5 NEEL - SC2G - Semi-conducteurs à large bande interdite
6 IEF - Institut d'électronique fondamentale

Scanning tunneling spectroscopies in the subkelvin temperature range were performed on superconducting silicon epilayers doped with boron in the atomic percent range. The resulting local differential conductance behaved as expected for a homogeneous superconductor, with an energy-gap dispersion below +/- 10%. The spectral shape, the amplitude, and temperature dependence of the superconductivity gap follow the BCS model, bringing support to the hypothesis of a hole pairing mechanism mediated by phonons in the weak-coupling limit.

Domaines: Supraconductivité [cond-mat.supr-con]

Franck Dahlem, Thierry Kociniewski, C. Marcenat, Audrey Grockowiak, Laëtitia Pascal, et al.. Subkelvin tunneling spectroscopy showing Bardeen-Cooper-Schrieffer superconductivity in heavily boron-doped silicon epilayers. Physical Review B: Condensed Matter and Materials Physics (1998-2015), 2010, 82 (14), pp.140505. ⟨10.1103/PhysRevB.82.140505⟩. ⟨hal-00735571⟩