Ph.D. Position in Scanning SQUID-on-tip imaging of 2D and van der Waals materials

Ph.D. Position in Scanning SQUID-on-tip imaging of 2D and van der Waals materials

Poggio Lab, Department of Physics

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The Department of Physics at the University of Basel offers a stimulating and collaborative environment with internationally recognized research groups active in both experimental and theoretical condensed matter physics. Our group is part of the Swiss Nanoscience Institute (nanoscience.ch) and the NCCR: Quantum Science and Technology (QSIT) (nccr-qsit.ethz.ch). More information is available at poggiolab.unibas.ch and www.physik.unibas.ch .

Your position

We seek a talented and ambitious Ph.D. Student interested in mesoscopic magnetic imaging experiments based on scanning nanometer-scale superconducting quantum interference devices (SQUIDs). Building on the pioneering work of the Zeldov group (Weizmann Institute) [1], we now produce and employ state-of-the-art SQUID-on-tip (SOT) as magnetic and thermal scanning probes in our lab in Basel [2,3]. These devices, which feature a nanometer-scale SQUID on the apex of a sharp scanning probe tip, have magnetic field sensitivities down to 5 nT/Hz1/2 [1], spatial resolutions better than 50 nm, and unmatched thermal sensitivities down to 1 μK/Hz1/2 [4].

With such exquisite resolution and sensitivity, we plan to study the recently discovered correlated states in twisted bilayer graphene and other van der Waals (vdW) materials. The manifestations of these states range from superconductivity, to highly insulating states, to potentially magnetic states. The fragility and sensitivity of the observed states to inhomogeneities has limited their macroscopic manifestation and complicates conventional transport or magnetization measurements, which integrate over an entire sample. Sensitive nanoscale imaging of these systems is urgently required to probe their local properties.

The ability to map magnetic field and dissipation sensitively and on the nanometer-scale overcomes ensemble or spatial inhomogeneity in systems ranging from arrays of nanometer-scale magnets, to superconducting thin films, to strongly correlated states in vdW heterostructures. Local imaging of nanometer-scale magnetization [2], local Meissner currents [5], or current in edge-states [6] is the key to unraveling the microscopic mechanisms behind a wealth of new and poorly understood condensed matter phenomena.

• Finkler et al., Nano Lett. 10, 1046 (2010); Vasyukov et al., Nat. Nanotechnol. 8, 639 (2013).
• Vasyukov et al., Nano Lett. 18, 964 (2018)
• Ceccarelli et al., arXiv:1907.05110 (2019).
• Halbertal et al., Nature 539, 407 (2016); Halbertal et al., Science 358, 6368 (2017).
• Embon et al., Nat. Commun. 8, 85 (2017).
• Marguerite et al., arXiv:1907.08973 (2019); Uri et al., arXiv:1908.02466 (2019); Uri et al., arXiv:1908.04595 (2019)

Your profile

Candidates with previous experimental physics or scanning probe microscopy experience are preferred. A Masters in physics or a related field is required. Applications should include the candidate's CV, copies of his/her diplomas, and 2 letters of reference.

We offer you

We offer the opportunity to conduct high-quality research in a dynamic and innovative scientific working environment. Salary is competitive and conditions of employment are governed by the personnel and salary regulations of the University of Basel.

All PhD fellows are expected to work in a team and collaborate with other PhD and postdoctoral fellows, as well as bachelor and master students joining the lab part of their time. Start of the project: as soon as possible. Duration: 4 years.

nanoscience.ch/en/research/phd-program