Electrons in Fractal Geometries

Projektinformationen

FRACTAL

ID Finanzhilfevereinbarung: 865570

DOI

10.3030/865570

Projekt abgeschlossen

EK-Unterschriftsdatum 12 Dezember 2019

Startdatum 1 September 2020

Enddatum 28 Februar 2026

Finanziert unter

• EXCELLENT SCIENCE - European Research Council (ERC)

Gesamtkosten

€ 2 718 750,00

EU-Beitrag

€ 2 718 750,00

Koordiniert durch

UNIVERSITEIT UTRECHT
Netherlands

Periodic Reporting for period 3 - FRACTAL (Electrons in Fractal Geometries)

Berichtszeitraum: 2023-09-01 bis 2025-02-28

Zusammenfassung vom Kontext und den Gesamtzielen des Projekts

The development of two-dimensional materials has enabled the discovery of new physical phenomena and led to the development of devices that are of crucial importance to our society. For example, we now base the definition of electrical resistance on the quantum Hall effect, a phenomenon exclusive to two dimensions. Similarly, the transistor that underpins every electronic device in use today relies on the manipulation of a two-dimensional electron gas. The realization that a material can have very different properties in two-dimensions compared to three-dimensions was a huge conceptual leap. In this project, a similar leap is taken: from integer (0,1,2,3) to non-integer, or fractional, dimensions. Specifically, we study (1) the properties of electrons in geometric fractals with dimension between 2 and 1. Fractals are objects that are self-similar on different length scales with two unique properties (i) a non-integer dimension and (ii) expansion symmetry but no periodicity. In addition, we aim to realize and experimentally characterize quasiparticles with fractional charge.

Arbeit, die ab Beginn des Projekts bis zum Ende des durch den Bericht erfassten Berichtszeitraums geleistet wurde, und die wichtigsten bis dahin erzielten Ergebnisse

To engineer geometric fractals, and lattices with quasiparticles with fractional charge, the tip of a scanning tunneling microscope is used to position adsorbates with atomic scale precision. First, we developed a new platform to create artificial lattices, based on Cs atoms on InAs(111)A. This material system provides an energy resolution that is much superior that that of CO/Cu(111). We studied the manipulation mechanism in detail and built the first artificial lattices. Furthermore, in collaboration with the group of Prof. Allan (Leiden University and LMU Munich), we developed, tested, and implemented a new generation high-frequency preamplifier that can be used to measure shot-noise in a scanning tunneling microscope. Measuring shot-noise can provide direct access to the charge of (quasi)particles.

Fortschritte, die über den aktuellen Stand der Technik hinausgehen und voraussichtliche potenzielle Auswirkungen (einschließlich der bis dato erzielten sozioökonomischen Auswirkungen und weiter gefassten gesellschaftlichen Auswirkungen des Projekts)

Our new amplifier significantly outperforms previous generations and enables experiments that were previously impossible. We will use this amplifier to study a variety of systems, ranging from superconductors to artificial lattices that host quasiparticles with fractional charge.