Spin–Orbit Interaction in a Two-Dimensional Hole Gas at the Surface of Hydrogenated Diamond

• Published in: Nano letters Vol. 15; no. 1; pp. 16 - 20
• Main Authors: Edmonds, Mark T, Willems van Beveren, Laurens H, Klochan, Oleh, Cervenka, Jiri, Ganesan, Kumar, Prawer, Steven, Ley, Lothar, Hamilton, Alexander R, Pakes, Christopher I
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 14-01-2015
• Subjects: Diamonds; Ferromagnetism; Insulating materials; Joining; Nanostructure; Orbits; Spin-orbit interactions; Two dimensional; surface conductivity; Diamond; spin−orbit interaction; 2DHG
• ISSN: 1530-6984; 1530-6992
• DOI: 10.1021/nl502081y

Hydrogenated diamond possesses a unique surface conductivity as a result of transfer doping by surface acceptors. Yet, despite being extensively studied for the past two decades, little is known about the system at low temperature, particularly whether a two-dimensional hole gas forms at the diamond surface. Here we report that (100) diamond, when functionalized with hydrogen, supports a p-type spin-3/2 two-dimensional surface conductivity with a spin–orbit interaction of 9.74 ± 0.1 meV through the observation of weak antilocalization effects in magneto-conductivity measurements at low temperature. Fits to 2D localization theory yield a spin relaxation length of 30 ± 1 nm and a spin-relaxation time of ∼0.67 ± 0.02 ps. The existence of a 2D system with spin orbit coupling at the surface of a wide band gap insulating material has great potential for future applications in ferromagnet–semiconductor and superconductor–semiconductor devices.