Heavy Fermions: electrons at the edge of magnetism

Majorana fermions in spin-singlet nodal superconductors with coexisting noncollinear magnetic order.

Realizations of Majorana fermions in solid state materials have attracted great interest recently in connection to topological order and quantum information processing. We propose a novel way to create Majorana fermions in superconductors. We show that an incipient noncollinear magnetic order turns a spin-singlet superconductor with nodes into a topological superconductor with a stable Majorana...

Direct measurement of proximity-induced magnetism at the interface between a topological insulator and a ferromagnet

When a topological insulator (TI) is in contact with a ferromagnet, both time-reversal and inversion symmetries are broken at the interface. An energy gap is formed at the TI surface, and its electrons gain a net magnetic moment through short-range exchange interactions. Magnetic TIs can host various exotic quantum phenomena, such as massive Dirac fermions, Majorana fermions, the quantum anomal...

Limited robustness of edge magnetism in zigzag graphene nanoribbons with electrodes.

It is shown that apart from well-known factors, like temperature, substrate, and edge reconstruction effects, also the presence of external contacts is destructive for the formation of magnetic moments at the edges of graphene nanoribbons (GNRs). The edge magnetism gradually decreases when graphene/electrode interfaces become more and more transparent for electrons. In addition to the graphene/...

Interplay of Superconductivity and Magnetism in the Two Dimensional Kondo Lattice Model

Since the original discovery of heavy fermion behavior in the late seventies by Andres et al. [1], heavy fermions keep attracting scientific interest due to their exotic and unusual properties. These are inter-metallic compounds that contain rare earth elements, like cerium, praseodymium, and ytterbium, and actinides like uranium. The term “heavy” refers to their large effective electronic mass...

Electron spin magnetism of zigzag graphene nanoribbon edge states