We have investigated the signal intensity, lineshape, spin-lattice and spin-spin (spin-echo decay) relaxation behavior of 11B nuclei in a Si[B] extrinsic semiconductor in the metallic state, as a function of magnetic field strength and temperature. We find that essentially all boron spins are in a highly symmetric environment, characterized by a mean nuclear quadrupole coupling constant (e2qQ/h) of ≈ 12 kHz. The spin-lattice relaxation is Korringa like, with a T1T ≈ 550 s K, at both 5 and 300 K, indicating a mean Knight shift of ≈ 70 ppm. The spin-spin relaxation time, T2E, is 25 ms at 8.45 T, independent of temperature, or magnetic field strength in the range 2.35 to 11.7 T, at 300 K. The T2E value is in good agreement with the predictions of a model of homonuclear dipolar interactions within metallic Si[B] clusters.
ASJC Scopus subject areas
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry