|Coherence properties of shallow donors in ZnO|
|Kai-Mei Fu (University of Washington)|
|ABC Physics (Atomic/Bio/Condensed Matter) Seminar|
Date: Thursday, February 1, 2018 12:30 PM
Location: PAB C-520
After a brief overview of the desired properties for
defect-based quantum bits, I present recent measurements on the coherence
properties of donor-bound electrons in ZnO.
Using all-optical spin control, we find a longitudinal relaxation time T1
exceeding 100 ms, an inhomogeneous dephasing time T2* of 17 nanoseconds, and a
Hahn spin-echo time T2 of 50 microseconds. The magnitude of T2* is consistent
with the inhomogeneity of the nuclear hyperfine field in natural ZnO. Possible mechanisms limiting T2 include
instantaneous diffusion and nuclear spin diffusion (spectral diffusion). These
results are comparable to the phosphorous donor system in natural silicon, suggesting
that with isotope and chemical purification long qubit coherence times can be
obtained for donor spins in a direct band gap semiconductor.