Dopant-Free Single Electron Pumps for Quantum Metrology*

At low temperature, we have observed low-disorder quantized conductance in quantum wires fabricated in dopant-free GaAs/AlGaAs two-dimensional electron gases (2DEG) with mobilities up to 7x10⁶ cm²/Vs (at 2.9x10¹¹ /cm²), with a 1D subband energy level spacing that can be tuned from 1 meV to more than 5 meV on individual devices. The absence of (intentional) dopants produces an environment with ultra low disorder [1] and very little charge noise [2]. Single electron pumps [3,4] were fabricated and measured at 1 GHz, with up to 3 quantized current plateaus observed. Thus, dopant-free quantum wires provide a unique platform to investigate electron-electron interactions, and could offer a path towards single electron pumps suitable for a quantum current standard [5].

[1] S. Sarkozy et al., PRB 79, 161307(R) (2009)
[2] W. Y. Mak et al., APL 102, 103507 (2013)
[3] S. P. Giblin et al., Nat. Comm. 3, 930 (2012)
[4] N. Ubbelohde et al., Nat. Nanotech. 10, 46 (2015)
[5] N. H. Kaneko et al., Meas. Sci. Technol. 27, 032001 (2016)