Abstract
Fragile quantum effects such as single electron charging in quantum dots or macroscopic coherent tunneling in superconducting junctions are the basis of modern quantum technologies. These phenomena can only be observed in devices where the characteristic spacing between energy levels exceeds the thermal energy, kBT, demanding effective refrigeration techniques for nanoscale electronic devices. Commercially available dilution refrigerators have enabled typical electron temperatures in the 10 to 100 mK regime, however indirect cooling of nanodevices becomes inefficient due to stray radiofrequency heating and weak thermal coupling of electrons to the device substrate. Here, we report on passing the millikelvin barrier for a nanoelectronic device. Using a combination of on-chip and off-chip nuclear refrigeration, we reach an ultimate electron temperature of Te = 421 ± 35 μK and a hold time exceeding 85 h below 700 μK measured by a self-calibrated Coulomb-blockade thermometer.
Highlights
1234567890():,; Accessing the microkelvin regime[1] holds the potential of enabling the observation of exotic electronic states, such as topological ordering[2], electron-nuclear ferromagnets[3,4], p-wave superconductivity[5], or non-Abelian anyons[6] in the fractional quantum Hall regime[7]
If only Zeeman splitting is present, which is linear in B, the ultimate temperature is limited by the decreasing molar heat capacity, Cn = αB2∕T2 in the presence prefactor α 1⁄4 N0IðI þ 1Þμ2ng of finite heat leaks, 2 n
The magnetic field required for magnetic cooling was applied by a superconducting solenoid with a rated field of 13 T
Summary
1234567890():,; Accessing the microkelvin regime[1] holds the potential of enabling the observation of exotic electronic states, such as topological ordering[2], electron-nuclear ferromagnets[3,4], p-wave superconductivity[5], or non-Abelian anyons[6] in the fractional quantum Hall regime[7]. By demagnetization cooling of all components together, we greatly reduce the heat leak to the nanoscale device, enabling both a record low final electron temperature and long hold times in excess of 85 h, demonstrating the viable utilization for quantum transport experiments in the microkelvin regime. We attach the copper frame (1.7 mol total, 0.32 mol effective amount) to the mixing chamber via an aluminum-foil heat switch[28], which is activated by a small solenoid at ≈ 10 mT of applied magnetic field.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
