Tunable Fermi level and hedgehog spin texture in gapped graphene

Abstract

Spin and pseudospin in graphene are known to interact under enhanced spin–orbit interaction giving rise to an in-plane Rashba spin texture. Here we show that Au-intercalated graphene on Fe(110) displays a large (∼230 meV) bandgap with out-of-plane hedgehog-type spin reorientation around the gapped Dirac point. We identify two causes responsible. First, a giant Rashba effect (∼70 meV splitting) away from the Dirac point and, second, the breaking of the six-fold graphene symmetry at the interface. This is demonstrated by a strong one-dimensional anisotropy of the graphene dispersion imposed by the two-fold-symmetric (110) substrate. Surprisingly, the graphene Fermi level is systematically tuned by the Au concentration and can be moved into the bandgap. We conclude that the out-of-plane spin texture is not only of fundamental interest but can be tuned at the Fermi level as a model for electrical gating of spin in a spintronic device.

Unraveling the association between genetic integrity and metabolic activity in pre-implantation stage embryos

“…However, Drosophila, Zebrafish and Xenopus embryos carrying DNA lesions failed to arrest even when DNA synthesis was inhibited by aphidicolin8910. Similarly, about half of the human embryos derived in vitro are known to possess chromosomal abnormalities even while being developmentally and morphologically indistinguishable from euploid embryos11. This is mainly due to the fact that human embryos in the preimplantation stage are prone to genomic errors thus acquire increased incidence of DNA abnormalities which is further propagated by the increased expression of cell cycle drivers and inadequately expressed cell cycle check point regulators1213.…”

Evidence of large spin-orbit coupling effects in quasi-free-standing graphene on Pb/Ir(1 1 1)

“…This places 2D materials, thin films and heterostructures in a focus of intense research [14][15][16][17][18]. In particular, significant attention is being paid to the enhancement of SOC in graphene [19][20][21][22][23][24][25][26][27][28][29][30][31][32], which would be an important extension of its properties enabling a number of interesting applications. For example, if in addition to the unavoidable Rashba term, that appears in supported graphene [33][34][35], the substrate is magnetically ordered and induces an exchange coupling by proximity [36], then the system might exhibit a quantum anomalous Hall effect [37].…”

Rashba splitting of 100 meV in Au-intercalated graphene on SiC

“…We show that this giant splitting is due to hybridization and much more limited in energy and momentum space than for Au-intercalated graphene on Ni. In a future spintronics, graphene could be used in various ways: as efficient leads for spin currents due to low spin-orbit interaction and large spin relaxation lengths [1], as ferromagnetic graphene due to a proximity magnetization [2], as spin filter when a large Rashba type spin-orbit interaction and a band gap at the Dirac point are imposed by a substrate [3], or when the spin-orbit interaction is strongly enhanced by covalently bonded adatoms [4]. The Rashba effect on a graphene Dirac cone leads to a complex band topology with a gapped and an ungapped cone similar to spinless bilayer graphene [5,6].…”