Quantized conductance of one-dimensional strongly correlated electrons in an oxide heterostructure

• Published in: Physical review. B 2019-03, Vol.99 (12), Article 121302
• Main Authors: Hou, H., Kozuka, Y., Liao, Jun-Wei, Smith, L. W., Kos, D., Griffiths, J. P., Falson, J., Tsukazaki, A., Kawasaki, M., Ford, C. J. B.
• Format: Article
• Language: English
• Subjects: Anomalies; Electron density; Electron transport; Electrons; Group III-V semiconductors; Heterostructures; Quantum computing; Qubits (quantum computing); Resistance; Spintronics; Zinc oxide
• ISSN: 2469-9950; 2469-9969
• DOI: 10.1103/PhysRevB.99.121302

Oxide heterostructures are versatile platforms with which to research and create novel functional nanostructures. We successfully develop one-dimensional (1D) quantum-wire devices using quantum point contacts on MgZnO/ZnO heterostructures and observe ballistic electron transport with conductance quantized in units of 2 e 2 / h . Using dc-bias and in-plane field measurements, we find that the g factor is enhanced to around 6.8, more than three times the value in bulk ZnO. We show that the effective mass m ∗ increases as the electron density decreases, resulting from the strong electron-electron interactions. In this strongly interacting 1D system we study features matching the “0.7” conductance anomalies up to the fifth subband. This Rapid Communication demonstrates that high-mobility oxide heterostructures such as this can provide good alternatives to conventional III-V semiconductors in spintronics and quantum computing as they do not have their unavoidable dephasing from nuclear spins. This paves a way for the development of qubits benefiting from the low defects of an undoped heterostructure together with the long spin lifetimes achievable in silicon.