Exotic Electronic Effect Found in a 2D Topological Material

Jülich, 26 September 2022 – Jülich researchers have been able to demonstrate an exotic electronic state, so-called Fermi Arcs, for the first time in a 2D material. The surprising appearance of Fermi arcs in such a material provides a link between novel quantum materials and their respective potential applications in a new generation of spintronics and quantum computing. The results have recently been published in Nature Communications.

Scientific Achievement

The newly detected Fermi arcs represent special - arc-like - deviations from the so-called Fermi surface. The Fermi surface is used in condensed matter physics to describe the momentum distribution of electrons in a metal. Normally, these Fermi surfaces represent closed surfaces. Exceptions such as the Fermi arcs are very rare and often are associated with exotic properties like superconductivity, negative magnetoresistance and anomalous quantum transport effects.

Societal and Scientific Relevance

Today’s oncoming technology challenge is to develop the “on-demand” control of physical properties in materials. However, such experimental tests have been largely limited to bulk materials and are key grand challenges in condensed matter science. With its groundbreaking paradigm, the findings present a promising new frontier for quantum control of topological states in low-dimensional systems by external means – the external magnetic field that offers unprecedented capabilities on 2D materials for artificial intelligence as well as future information processing.

Further Details

The analysed material is a so-called topological 2D material. Topological materials have special properties that arise due to interactions of the electrons with the crystal structure and are protected against interfering influences. 2D materials, on the other hand, are materials that consist of only one layer of atoms or molecules and are being intensively researched because of their unusual properties. A well-known example is graphene, which consists of single-layer carbon.

Graphene exhibits exotic physical properties compared with its bulk counterpart. The material mentioned in the paper is a 2D Iron atomic layer. When compared with graphene, these 2D hybrid magnets are a class of materials that reveal additional emergent phenomena in the single layer limit. For instance, it can lead to potential applications of the chiral anomaly in devices and open a new area of research in the field of the strongly-correlated topological materials.

For the work, the researchers conducted experiments at the Elettra Synchrotron in Trieste, Italy. There, an international consortium led by Forschungszentrum Jülich operates the spin-resolving Momentum Microscope at the NanoESCA beamline.

Außergewöhnlicher elektronischer Effekt in einem topologischen 2D-Material nachgewiesen
a) Measured spin-resolved Fermi arcs in 2 MLs Fe/W(110) on the left and on the right side of the momentum map. Colours indicate the in-plane spin component along the x direction, which is orthogonal to the sample magnetization b) Arrows denote the complete theoretical spin texture in momentum space, revealing a prominent non-collinearity for the Fermi arcs (red) as compared to the interior states (grey). C) Distribution of the theoretical momentum-space Berry curvature of all occupied bands in 2 MLs Fe/W(110), around one of the pairs of Fermi arcs.
Ying-Jiun Chen et al, Nature Communications, https://doi.org/10.1038/s41467-022-32948-z (CC-BY)

Original publication:

Chen, YJ., Hanke, JP., Hoffmann, M. et al.
Spanning Fermi arcs in a two-dimensional magnet.
Nat Commun
13, 5309 (9 September 2022). DOI: 10.1038/s41467-022-32948-z


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