Quasi-two-dimensional electron gas at the oxide interfaces for topological quantum physics

¹ Unité Mixte de Physique, CNRS, Thales, Université Paris- Saclay - F-91767 Palaiseau, France
² Laboratoire de Physique et d'Etude des Matériaux, ESPCI Paris, PSL Research University, CNRS F-75005 Paris, France
³ Kavli Institute of Nanoscience, Delft University of Technology - P.O. Box 5046, 2600 GA Delft, Netherlands
⁴ Dipartimento di Fisica “E. R. Caianiello”, Università degli Studi di Salerno - I-84084 Fisciano (SA), Italy
⁵ CNR- SPIN - Via Giovanni Paolo II, 132, I-84084 Fisciano (SA), Italy
⁶ Department of Microtechnology and Nanoscience- MC2, Chalmers University of Technology SE-41296 Gothenburg, Sweden
⁷ Department of Physics and Institute of Nanotechnology and Advanced Materials, Bar- Ilan University Ramat-Gan, Israel
⁸ Dipartimento di Fisica “E. Pancini”, Università Federico II di Napoli - Complesso Monte S. Angelo, I-80126 Napoli, Italy
⁹ GFMC, Departamento de Fisica de Materiales, Universidad Complutense de Madrid - E-28040 Madrid, Spain
¹⁰ CNR- SPIN, Complesso Monte S. Angelo - Via Cinthia, I-80126 Napoli, Italy

^(a) marco.salluzzo@spin.cnr.it

Received: 21 November 2020
Accepted: 13 January 2021

Abstract

The development of “fault-tolerant” quantum computers, unaffected by noise and decoherence, is one of the fundamental challenges in quantum technology. One of the approaches currently followed is the realization of “topologically protected” qubits which make use of quantum systems characterized by a degenerate ground state of composite particles, known as “non-Abelian anyons”, able to encode and manipulate quantum information in a non-local manner. In this paper, we discuss the potential of quasi-two-dimensional electron gas (q2DEG) at the interface between band insulating oxides, like LaAlO₃ and SrTiO₃, as an innovative technological platform for the realization of topological quantum systems. Being characterized by a unique combination of unconventional spin-orbit coupling, magnetism, and 2D-superconductivity, these systems naturally possess most of the fundamental characteristics needed for the realization of a topological superconductor. These properties can be widely tuned by electric field effect acting on the orbital splitting and occupation of the non-degenerate 3d_xy and 3d_{xz, yz} bands. The topological state in oxide q2DEGs quasi-one-dimensional nanochannels could be therefore suitably controlled, leading to conceptual new methods for the realization of a topological quantum electronics based on the tuning of the orbital degrees of freedom.