Statistical evaluation of 571 GaAs quantum point contact transistors showing the 0.7 anomaly in quantized conductance using cryogenic on-chip multiplexing
Pengcheng Ma,
Kaveh Delfanazari,
Reuben K. Puddy,
Jiahui Li,
Moda Cao,
Teng Yi,
Jonathan P. Griffiths,
Harvey E. Beere,
David A. Ritchie,
Michael J. Kelly,
Charles G. Smith
Affiliations
Pengcheng Ma
Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge CB3 0HE, UK
Kaveh Delfanazari
Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge CB3 0HE, UK; James Watt School of Engineering, University of Glasgow, Glasgow G12 8QQ, UK; Electrical Engineering Division, University of Cambridge, Cambridge CB3 0FA, UK; Corresponding author.
Reuben K. Puddy
Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge CB3 0HE, UK
Jiahui Li
Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge CB3 0HE, UK
Moda Cao
Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge CB3 0HE, UK
Teng Yi
Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge CB3 0HE, UK
Jonathan P. Griffiths
Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge CB3 0HE, UK
Harvey E. Beere
Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge CB3 0HE, UK
David A. Ritchie
Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge CB3 0HE, UK
Michael J. Kelly
Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge CB3 0HE, UK; Electrical Engineering Division, University of Cambridge, Cambridge CB3 0FA, UK
Charles G. Smith
Cavendish Laboratory, Department of Physics, University of Cambridge, Cambridge CB3 0HE, UK
The mass production and the practical number of cryogenic quantum devices producible in a single chip are limited to the number of electrical contact pads and wiring of the cryostat or dilution refrigerator. It is, therefore, beneficial to contrast the measurements of hundreds of devices fabricated in a single chip in one cooldown process to promote the scalability, integrability, reliability, and reproducibility of quantum devices and to save evaluation time, cost and energy. Here, we used a cryogenic on-chip multiplexer architecture and investigated the statistics of the 0.7 anomaly observed on the first three plateaus of the quantized conductance of semiconductor quantum point contact (QPC) transistors. Our single chips contain 256 split gate field-effect QPC transistors (QFET) each, with two 16-branch multiplexed source-drain and gate pads, allowing individual transistors to be selected, addressed and controlled through an electrostatic gate voltage process. A total of 1280 quantum transistors with nano-scale dimensions are patterned in 5 different chips of GaAs heterostructures. From the measurements of 571 functioning QFETs taken at temperatures T = 1.4 K and T = 40 mK, it is found that the spontaneous polarisation model and Kondo effect do not fit our results. Furthermore, some of the features in our data largely agreed with van Hove model with short-range interactions. Our approach provides further insight into the quantum mechanical properties and microscopic origin of the 0.7 anomaly in QFETs, paving the way for the development of semiconducting quantum circuits and integrated cryogenic electronics, for scalable quantum logic control, readout, synthesis, and processing applications.
