Nanowire Superinductors
Licentiate thesis, 2018

In this thesis, we demonstrate that a disordered superconductor with a high kinetic inductance can realize a low microwave loss, non-dissipative circuit element with an impedance greater than the quantum resistance (Rq = h/4e^2 = 6.5kΩ). This element, known as a superinductor, can produce a quantum circuit where charge fluctuations are suppressed.

We have fabricated and characterized 20nm thick niobium-nitride nanowires with a width of 40nm, implementing a superinductance with impedance Z = 6.795kΩ. We demonstrate internal quality factors Qi = 2.5×10^4 at single photon excitation, which is significantly higher than values reported in devices with similar materials and geometries. Moreover, we show that the dominant dissipation in our nanowires is not an intrinsic property of the disordered films, but can instead be fully understood within the well-studied framework of two-level systems.

Disordered Superconductors

Superinductance

Superinductor

Resonator

Nanowire

TLS

Author

David Niepce

Chalmers, Microtechnology and Nanoscience (MC2), Quantum Device Physics

Superinductance for very long-lived quantum coherence

Chalmers, 2013-10-01 -- 2014-06-30.

Areas of Advance

Nanoscience and Nanotechnology (2010-2017)

Subject Categories

Other Physics Topics

Other Electrical Engineering, Electronic Engineering, Information Engineering

Condensed Matter Physics

Infrastructure

Nanofabrication Laboratory

Technical report MC2 - Department of Microtechnology and Nanoscience, Chalmers University of Technology: MC2-392

Publisher

Chalmers University of Technology

More information

Latest update

8/15/2018