Electron Spin Coherence of Silicon Vacancies in Proton-Irradiated 4H-SiC
Abstract
We report T2 spin coherence times for electronic states localized in Si vacancies in 4HSiC. Our spin coherence study included two SiC samples that were irradiated with 2 MeV protons at different fluences (10(exp 13) and 10(exp 14)cm(exp -2) in order to create samples with unique defect concentrations. Using optically detected magnetic resonance and spin echo, the coherence times for each sample were measured across a range of temperatures from 8 to 295 K. All echo experiments were done at a magnetic field strength of 0.371 T and a microwave frequency of 10.49 GHz. The longest coherence times were obtained at 8 K, being 270 + or - 61 microsecond for the 10(exp 13)cm(exp -2) proton-irradiated sample and 104 + or - 17 microsecond for the 10(exp 14)cm(exp -2) sample. The coherence times for both samples displayed unusual temperature dependencies; in particular, they decreased with temperature until 60 K, then increased until 160 K, then decreased again. This increase between 60 and 160 K is tentatively attributed to a motional Jahn-Teller effect. The consistently longer lifetimes for the 10(exp 13)cm(exp -2) sample suggest that a significant source of the spin dephasing can be attributed to dipole-dipole interactions between Si vacancies or with other defects produced by the proton irradiation. The lack of a simple exponential decay for our 1014cm2 sample indicates an inhomogeneous distribution of defect spins.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jan 17, 2017
- Accession Number
- AD1113719
Entities
People
- B. D. Weaver
- Evan R. Glaser
- J. S. Colton
- J. S. Embley
- K. G. Miller
- M. A. Morris
- Michael A. Meehan
- S. G. Carter
- S. L. Crossen
Organizations
- United States Naval Research Laboratory