Figure 4
From: Enhanced electron-phonon coupling for a semiconductor charge qubit in a surface phonon cavity
Phonon assisted tunneling in a DQD.
(a) Schematic of the time-gated measurement setup. The left ohmic contact is used as an in-plane gate to extract solely the phonon assisted tunneling spectrum. Current is re-routed to flow from the bottom channel, through the DQD to the right ohmic contact. (b) Excitation voltage dependence of the splitting in resonant tunneling peaks. Phonon/photon assisted tunneling sidebands are observed with separations in the unit of hf. Measured data (red circles) can be reproduced by theoretical fits (solid black lines), which suggests emission and absorption of integer numbers of phonons by the DQD. (c) Frequency dependence of the current profile under the pulse sequence shown in the inset. Phonon assisted tunneling spectra, labeled SAW, show a splitting of ±hf (marked by vertical lines) only at the resonant frequency (Δf = 0). The other spectra, labeled ‘EM+SAW’, are excited by the mixture. The two sets of spectra are separated by the application of the square voltage pulse VIPG. Data in (b,c) are taken at 30 mK.
