1. Hole Spin Decoherence in Quantum Dots
Denis Bulaev and Daniel Loss
Department of Physics
University of Basel, Switzerland

2. Motivation Pros of heavy hole Cons of heavy hole Quantum computing
Qubit with long coherence time
Pros of heavy hole
Weak hyperfine interactions with nuclei (p-symmetry)
Cons of heavy hole
Strong spin-orbit interactions with light holes
Difficulties in coherent spin manipulation
...

3. Motivation Pros of heavy hole Cons of heavy hole Quantum computing
Qubit with long coherence time
Pros of heavy hole
Weak hyperfine interactions with nuclei (p-symmetry)
Weak spin-orbit interactions with light holes in 2D QDs
Cons of heavy hole
Difficulties in coherent spin manipulation
...

4. Motivation Pros of heavy hole Cons of heavy hole Quantum computing
Qubit with long coherence time
Pros of heavy hole
Weak hyperfine interactions with nuclei (p-symmetry)
Weak spin-orbit interactions with light holes in 2D QDs
Possibilities for coherent spin manipulation via EDSR
Cons of heavy hole
...

5. Effective Hamiltonian of Heavy Holes
[R. Winkler, PRB 62, 4245 (2000)]
[DB & D. Loss, PRL 95, (2006)]
g(GaAs) = 2.5,
g(InAs) = -2.2.
[H.W. van Kestern, et al., PRB 41, 5283 (1990)]
[M.Bayer,et al., PRL 82, 1748 (1999)]

6. Spin Relaxation Rates GaAs Quantum Dot (g = 2.5)
InAs Quantum Dot (g = -2.2)
[DB & D. Loss, PRL 95, (2006)]

7. B-field Dependence of Rates
Electrons
phonons
Hso
Heavy holes
Dresselhaus SO coupling
Rashba SO coupling

8. Summary Anticrossing and spin mixing (GaAs QD)
T2 = 2T1 at low temperatures
Peaks on the spin relaxation decay curve (GaAs QD)
Rashba Dresselhaus
Spin relaxation time for heavy holes CAN BE longer than for electrons