High quality factor graphene-based 2D heterostructure mechanical resonator

TL;DR

This paper presents a novel graphene-based heterostructure resonator with high quality factors and low electrical losses, suitable for quantum sensing and transduction applications.

Contribution

It introduces a hybrid NbSe₂-graphene resonator with significantly improved quality factors and reduced electrical losses compared to pure graphene devices.

Findings

Achieved quality factors up to 245,000 at low temperatures

Reduced electrical losses due to NbSe₂ layer resistivity

Potential for integration into quantum circuits

Abstract

Ultralight mechanical resonators based on low-dimensional materials are well suited as exceptional transducers of minuscule forces or mass changes. However, the low dimensionality also provides a challenge to minimize resistive losses and heating. Here, we report on a novel approach that aims to combine different 2D materials to tackle this challenge. We fabricated a heterostructure mechanical resonator consisting of few layers of niobium diselenide (NbSe$_2$) encapsulated by two graphene sheets. The hybrid membrane shows high quality factors up to 245'000 at low temperatures, comparable to the best few-layer graphene mechanical resonators. In contrast to few-layer graphene resonators, the device shows reduced electrical losses attributed to the lower resistivity of the NbSe$_2$ layer. The peculiar low temperature dependence of the intrinsic quality factor points to dissipation over two-level systems which in turn relax over the electronic system. Our high sensitivity readout is enabled by coupling the membrane to a superconducting cavity which allows for the integration of the hybrid mechanical resonator as a sensitive and low loss transducer in future quantum circuits.