1
|
Danilin S, Barbosa J, Farage M, Zhao Z, Shang X, Burnett J, Ridler N, Li C, Weides M. Engineering the microwave to infrared noise photon flux for superconducting quantum systems. EPJ Quantum Technol 2022; 9:1. [PMID: 35098151 PMCID: PMC8761155 DOI: 10.1140/epjqt/s40507-022-00121-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 01/03/2022] [Indexed: 06/14/2023]
Abstract
Electromagnetic filtering is essential for the coherent control, operation and readout of superconducting quantum circuits at milliKelvin temperatures. The suppression of spurious modes around transition frequencies of a few GHz is well understood and mainly achieved by on-chip and package considerations. Noise photons of higher frequencies - beyond the pair-breaking energies - cause decoherence and require spectral engineering before reaching the packaged quantum chip. The external wires that pass into the refrigerator and go down to the quantum circuit provide a direct path for these photons. This article contains quantitative analysis and experimental data for the noise photon flux through coaxial, filtered wiring. The attenuation of the coaxial cable at room temperature and the noise photon flux estimates for typical wiring configurations are provided. Compact cryogenic microwave low-pass filters with CR-110 and Esorb-230 absorptive dielectric fillings are presented along with experimental data at room and cryogenic temperatures up to 70 GHz. Filter cut-off frequencies between 1 to 10 GHz are set by the filter length, and the roll-off is material dependent. The relative dielectric permittivity and magnetic permeability for the Esorb-230 material in the pair-breaking frequency range of 75 to 110 GHz are measured, and the filter properties in this frequency range are calculated. The estimated dramatic suppression of the noise photon flux due to the filter proves its usefulness for experiments with superconducting quantum systems.
Collapse
Affiliation(s)
- Sergey Danilin
- James Watt School of Engineering, University of Glasgow, Glasgow, G12 8QQ UK
| | - João Barbosa
- James Watt School of Engineering, University of Glasgow, Glasgow, G12 8QQ UK
| | - Michael Farage
- James Watt School of Engineering, University of Glasgow, Glasgow, G12 8QQ UK
| | - Zimo Zhao
- James Watt School of Engineering, University of Glasgow, Glasgow, G12 8QQ UK
| | - Xiaobang Shang
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW UK
| | - Jonathan Burnett
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW UK
| | - Nick Ridler
- National Physical Laboratory, Hampton Road, Teddington, TW11 0LW UK
| | - Chong Li
- James Watt School of Engineering, University of Glasgow, Glasgow, G12 8QQ UK
| | - Martin Weides
- James Watt School of Engineering, University of Glasgow, Glasgow, G12 8QQ UK
| |
Collapse
|
2
|
Fernández-Lomana M, Wu B, Martín-Vega F, Sánchez-Barquilla R, Álvarez-Montoya R, Castilla JM, Navarrete J, Marijuan JR, Herrera E, Suderow H, Guillamón I. Millikelvin scanning tunneling microscope at 20/22 T with a graphite enabled stick-slip approach and an energy resolution below 8 μeV: Application to conductance quantization at 20 T in single atom point contacts of Al and Au and to the charge density wave of 2H-NbSe 2. Rev Sci Instrum 2021; 92:093701. [PMID: 34598511 DOI: 10.1063/5.0059394] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2021] [Accepted: 08/21/2021] [Indexed: 06/13/2023]
Abstract
We describe a scanning tunneling microscope (STM) that operates at magnetic fields up to 22 T and temperatures down to 80 mK. We discuss the design of the STM head, with an improved coarse approach, the vibration isolation system, and efforts to improve the energy resolution using compact filters for multiple lines. We measure the superconducting gap and Josephson effect in aluminum and show that we can resolve features in the density of states as small as 8 μeV. We measure the quantization of conductance in atomic size contacts and make atomic resolution and density of states images in the layered material 2H-NbSe2. The latter experiments are performed by continuously operating the STM at magnetic fields of 20 T in periods of several days without interruption.
Collapse
Affiliation(s)
- Marta Fernández-Lomana
- Laboratorio de Bajas Temperaturas y Altos Campos Magnéticos, Unidad Asociada (UAM/CSIC), Departamento de Física de la Materia Condensada, Instituto Nicolás Cabrera and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Beilun Wu
- Laboratorio de Bajas Temperaturas y Altos Campos Magnéticos, Unidad Asociada (UAM/CSIC), Departamento de Física de la Materia Condensada, Instituto Nicolás Cabrera and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Francisco Martín-Vega
- Laboratorio de Bajas Temperaturas y Altos Campos Magnéticos, Unidad Asociada (UAM/CSIC), Departamento de Física de la Materia Condensada, Instituto Nicolás Cabrera and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Raquel Sánchez-Barquilla
- Laboratorio de Bajas Temperaturas y Altos Campos Magnéticos, Unidad Asociada (UAM/CSIC), Departamento de Física de la Materia Condensada, Instituto Nicolás Cabrera and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Rafael Álvarez-Montoya
- Laboratorio de Bajas Temperaturas y Altos Campos Magnéticos, Unidad Asociada (UAM/CSIC), Departamento de Física de la Materia Condensada, Instituto Nicolás Cabrera and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - José María Castilla
- Departamento de Física de la Materia Condensada, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - José Navarrete
- SEGAINVEX, Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | | | - Edwin Herrera
- Laboratorio de Bajas Temperaturas y Altos Campos Magnéticos, Unidad Asociada (UAM/CSIC), Departamento de Física de la Materia Condensada, Instituto Nicolás Cabrera and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Hermann Suderow
- Laboratorio de Bajas Temperaturas y Altos Campos Magnéticos, Unidad Asociada (UAM/CSIC), Departamento de Física de la Materia Condensada, Instituto Nicolás Cabrera and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| | - Isabel Guillamón
- Laboratorio de Bajas Temperaturas y Altos Campos Magnéticos, Unidad Asociada (UAM/CSIC), Departamento de Física de la Materia Condensada, Instituto Nicolás Cabrera and Condensed Matter Physics Center (IFIMAC), Universidad Autónoma de Madrid, E-28049 Madrid, Spain
| |
Collapse
|
3
|
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.
Collapse
|
4
|
Nicolí G, Märki P, Bräm BA, Röösli MP, Hennel S, Hofmann A, Reichl C, Wegscheider W, Ihn T, Ensslin K. Quantum dot thermometry at ultra-low temperature in a dilution refrigerator with a 4He immersion cell. Rev Sci Instrum 2019; 90:113901. [PMID: 31779415 DOI: 10.1063/1.5127830] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Accepted: 10/26/2019] [Indexed: 06/10/2023]
Abstract
Experiments performed at a temperature of a few millikelvins require effective thermalization schemes, low-pass filtering of the measurement lines, and low-noise electronics. Here, we report on the modifications to a commercial dilution refrigerator with a base temperature of 3.5 mK that enable us to lower the electron temperature to 6.7 mK measured from the Coulomb peak width of a quantum dot gate-defined in an [Al]GaAs heteostructure. We present the design and implementation of a liquid 4He immersion cell tight against superleaks, implement an innovative wiring technology, and develop optimized transport measurement procedures.
Collapse
Affiliation(s)
- G Nicolí
- Solid State Physics Laboratory, ETH Zürich, Otto-Stern-Weg 1, 8093 Zürich, Switzerland
| | - P Märki
- Solid State Physics Laboratory, ETH Zürich, Otto-Stern-Weg 1, 8093 Zürich, Switzerland
| | - B A Bräm
- Solid State Physics Laboratory, ETH Zürich, Otto-Stern-Weg 1, 8093 Zürich, Switzerland
| | - M P Röösli
- Solid State Physics Laboratory, ETH Zürich, Otto-Stern-Weg 1, 8093 Zürich, Switzerland
| | - S Hennel
- Solid State Physics Laboratory, ETH Zürich, Otto-Stern-Weg 1, 8093 Zürich, Switzerland
| | - A Hofmann
- Solid State Physics Laboratory, ETH Zürich, Otto-Stern-Weg 1, 8093 Zürich, Switzerland
| | - C Reichl
- Solid State Physics Laboratory, ETH Zürich, Otto-Stern-Weg 1, 8093 Zürich, Switzerland
| | - W Wegscheider
- Solid State Physics Laboratory, ETH Zürich, Otto-Stern-Weg 1, 8093 Zürich, Switzerland
| | - T Ihn
- Solid State Physics Laboratory, ETH Zürich, Otto-Stern-Weg 1, 8093 Zürich, Switzerland
| | - K Ensslin
- Solid State Physics Laboratory, ETH Zürich, Otto-Stern-Weg 1, 8093 Zürich, Switzerland
| |
Collapse
|