Evidence for coherent transport in GaAs hole open quantum dots.

We report magnetotransport measurements in GaAs hole open quantum dots. Our samples were fabricated from a $p$-type GaAs quantum well with a density of $2.2 \times 10^{15} \ \rm m^{-2}$ and a mobility of $35 \ \rm m^2/Vs$. Two different dots were patterned using e-beam lithography and wet etching. A top gate was added in order to control the dots openings and the hole density. The measurements were performed down to 30 mK with the magnetic field applied perpendicular to the plane of the two- dimensional system. We observed large, reproducible conductance fluctuations associated with the coherent transport of holes inside the dots at lowest temperatures which vanish above 500 mK. From the variance of these fluctuations and from the Random Matrix Theory, we extracted the hole dephasing time $\tau_\varphi$. The temperature dependence of the calculated $\tau_\varphi$ lies between a $T^{-1}$ and $T^{-2}$ behavior and exhibits a saturation at very low temperature which is similar with $\tau_\varphi$ measured in 2D electron systems\footnote{B. Hackens \emph{et al.}, Phys. Rev. Lett. \textbf{94}, 146802 (2005)}.