Magnetic electron collimation in three-dimensional semi-metals
| Autor: | Xiangwei Huang, Carsten Putzke, Chunyu Guo, Jonas Diaz, Markus König, Horst Borrmann, Nityan L. Nair, James G. Analytis, Philip J.W. Moll |
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| Předmět: |
Condensed Matter - Materials Science
Condensed Matter - Mesoscale and Nanoscale Physics lens Materials Science (cond-mat.mtrl-sci) FOS: Physical sciences lcsh:Atomic physics. Constitution and properties of matter cond-mat.mtrl-sci semimetals lcsh:QC170-197 Mesoscale and Nanoscale Physics (cond-mat.mes-hall) cond-mat.mes-hall compensated metal transport lcsh:TA401-492 spatially inhomogeneous current lcsh:Materials of engineering and construction. Mechanics of materials fields |
| Zdroj: | npj Quantum Materials, vol 5, iss 1 npj Quantum Materials, Vol 5, Iss 1, Pp 1-7 (2020) npj Quantum Materials |
| Popis: | While electrons moving perpendicular to a magnetic field are confined to cyclotron orbits, they can move freely parallel to the field. This simple fact leads to complex current flow in clean, low carrier density semi-metals, such as long-ranged current jets forming along the magnetic field when currents pass through point-like constrictions. Occurring accidentally at imperfect current injection contacts, the phenomenon of "current jetting" plagues the research of longitudinal magneto-resistance which is particularly important in topological conductors. Here we demonstrate the controlled generation of tightly focused electron beams in a new class of micro-devices machined from crystals of the Dirac semi-metal Cd3As2. The current beams can be guided by tilting a magnetic field and their range tuned by the field strength. Finite element simulations quantitatively capture the voltage induced at faraway contacts when the beams are steered towards them, supporting the picture of controlled electron jets. These experiments demonstrate the first direct control over the highly nonlocal signal propagation unique to 3D semi-metals in the current jetting regime, and may lead to novel applications akin to electron optics in free space. 18 pages, 11 figures |
| Databáze: | OpenAIRE |
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