Constructing ab initio models of ultra-thin Al-AlOx-Al barriers

Abstract

The microscopic structure of ultra-thin oxide barriers often plays a major role in modern nano-electronic devices. In the case of superconducting electronic circuits, their operation depends on the electrical non-linearity provided by one or more such oxide layers in the form of ultra-thin tunnel barriers (also known as Josephson junctions). Currently available fabrication techniques manufacture an amorphous oxide barrier, which is attributed as a major noise source within the device. The nature of this noise is currently an open question and requires both experimental and theoretical investigation. Here, we present a methodology for constructing atomic scale computational models of Josephson junctions using a combination of molecular mechanics, empirical and ab initio methods. These junctions consist of ultra-thin amorphous aluminium-oxide layers sandwiched between crystalline aluminium. The stability and structure of these barriers as a function of density and stoichiometry are investigated, which we compare to experimentally observed parameters

7 pages, 4 figures, 1 table. For special issue dedicated to Prof. Ian Snook

References in corpus (8)

• Suppressing Charge Noise Decoherence in Superconducting Charge Qubits
• Single artificial-atom lasing
• Low- and high-frequency noise from coherent two-level systems
• Measuring the temperature dependence of individual two-level systems by direct coherent control
• Delocalised oxygen as the origin of two-level defects in Josephson junctions
• Phase-Coherent Dynamics of a Superconducting Flux Qubit with Capacitive-Bias Readout
• Microscopic model of critical current noise in Josephson-junction qubits: Subgap resonances and Andreev bound states
• Atomic delocalisation as a microscopic origin of two-level defects in Josephson junctions

Cited by in corpus (7)

• Towards understanding two-level-systems in amorphous solids -- Insights from quantum circuits
• Optimization of $Al/Al{O}_x/Al$-Layer Systems for Josephson Junctions from a Microstructure Point of View
• Simulating the fabrication of aluminium oxide tunnel junctions
• Intrinsically shunted Josephson junctions for electronics applications
• The effect of atomic structure on the electrical response of aluminium oxide tunnel junctions
• Structural details of Al/Al2O3 junctions and their role in formation of electron tunnel barriers
• Structural and Nanochemical Properties of AlOx Layers in $Al/Al{O}_x/Al$-Layer Systems for Josephson Junctions