Multiple Nuclear Polarization States in a Double Quantum Dot

We observe multiple stable states of nuclear polarization and nuclear self-tuning over a large range of fields in a double quantum dot under conditions of electron spin resonance. The observations can be understood within an elaborated theoretical rate equation model for the polarization in each of the dots, in the limit of strong driving. This...

InSitu Reduction of Charge Noise in GaAs/AlxGa1-xAs Schottky-Gated Devices

We show that an insulated electrostatic gate can be used to strongly suppress ubiquitous background charge noise in Schottky-gated GaAs=AlGaAs devices. Via a 2D self-consistent simulation of the conduction band profile we show that this observation can be explained by reduced leakage of electrons from the Schottky gates into the semiconductor...

Cryogenic amplifier for fast real-time detection of single-electron tunneling

The authors employ a cryogenic high electron mobility transistor (HEMT) amplifier to increase the bandwidth of a charge detection setup with a quantum point contact (QPC) charge sensor. The HEMT is operating at 1?K and the circuit has a bandwidth of 1?MHz. The noise contribution of the HEMT at high frequencies is only a few times higher than...

Experimental signature of phonon-mediated spin relaxation in a two-electron quantum dot

Nondestructive measurement of electron spins in a quantum dot

We propose and implement a nondestructive measurement that distinguishes between two-electron spin states in a quantum dot. In contrast to earlier experiments with quantum dots, the spins are left behind in the state corresponding to the measurement outcome. By measuring the spin states twice within a time shorter than the relaxation time T1,...

Single-shot readout of electron spin states in a quantum dot using spin-dependent tunnel rates

Spin filling of a quantum dot derived from excited-state spectroscopy

Semiconductor few-electron quantum dot operated as a bipolar spin filter