We investigate heavy-hole spin relaxation and decoherence in quantum dots in
perpendicular magnetic fields. We show that at low temperatures the spin
decoherence time is two times longer than the spin relaxation time. We find
that the spin relaxation time for heavy holes can be comparable to or even
longer than that for electrons in strongly two-dimensional quantum dots. We
discuss the difference in the magnetic-field dependence of the spin relaxation
rate due to Rashba or Dresselhaus spin-orbit coupling for systems with positive
(i.e., GaAs quantum dots) or negative (i.e., InAs quantum dots) g-factor.Comment: 5 pages, 1 figur