Dissipation of Intersubband Plasmons in Wide Quantum Wells

This Letter reports detailed measurements of the dissipation times ${\tau }_d$ of $\sim 10\mathrm{meV}$ intersubband (ISB) plasmons, and of the (single-particle) transport lifetimes ${\tau }_{\mu }$, in a remotely doped 40 nm GaAs quantum well. Introduced here as the time for ISB plasmons to dissipate into other modes of the electron gas, ${\tau }_d$ is deduced from the homogeneous ISB absorption linewidth, measured as a function of sheet concentration and perpendicular dc electric field. Modeling in this and the next Letter [C. A. Ullrich and G. Vignale, Phys. Rev. Lett. 87, 037402 (2001)] indicates that scattering from rough interfaces dominates ${\tau }_d$, while scattering from ionized impurities dominates ${\tau }_{\mu }$.