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Atomically thin dilute magnetism in Co-doped phosphorene
Two-dimensional dilute magnetic semiconductors can provide fundamental
insights in the very nature of magnetic orders and their manipulation through
electron and hole doping. Despite the fundamental physics, due to the large
charge density control capability in these materials, they can be extremely
important in spintronics applications such as spin valve and spin-based
transistors. In this article, we studied a two-dimensional dilute magnetic
semiconductors consisting of phosphorene monolayer doped with cobalt atoms in
substitutional and interstitial defects. We show that these defects can be
stabilized and are electrically active. Furthermore, by including holes or
electrons by a potential gate, the exchange interaction and magnetic order can
be engineered, and may even induce a ferromagnetic-to-antiferromagnetic phase
transition in p-doped phosphorene.Comment: 7 pages, 4 colorful figure
Phosphorene nanoribbons
Edge-induced gap states in finite phosphorene layers are examined using
analytical models and density functional theory. The nature of such gap states
depends on the direction of the cut. Armchair nanoribbons are insulating,
whereas nanoribbons cut in the perpendicular direction (with zigzag and
cliff-type edges) are metallic, unless they undergo a reconstruction or
distortion with cell doubling, which opens a gap. All stable nanoribbons with
unsaturated edges have gap states that can be removed by hydrogen passivation.
Armchair nanoribbon edge states decay exponentially with the distance to the
edge and can be described by a nearly-free electron model
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