First-principles analysis of intercalated Pb structures under buffer-layer graphene on SiC(0001): Pb(111)-, plumbene-, and amorphous-like Pb layers
Not Available
Han, Yong (ORCID:0000000154040911)↗
Engineering topics
Kolmer, Marek (ORCID:0000000267869697)
Publications and source records attributed to Kolmer, Marek (ORCID:0000000267869697).
Atomic-scale manipulation of buried graphene–silicon carbide interface by local electric field
Abstract Precision of scanning tunneling microscopy (STM) enables control of matter at scales of single atoms. However, transition from atomic-scale manipulation strategies to practical devices encounters fundamental problems in protection of the designer structures formed atop the surface. In this context, STM manipulation of subsurface structures on technologically relevant materials is encouraging. Here, we propose a material platform and protocols for precise manipulation of a buried graphene interface. We show that an electric field from the STM tip reversibly controls breaking and restoring of covalent bonds between the graphene buffer layer and the SiC substrate. The process involves charge redistribution at the atomically sharp interface plane under the epitaxial graphene layer(s). This buried manipulation platform is laterally defined by unit cells from the corresponding (6×6) SiC moiré lattice of the epitaxial graphene. Local and reversible electric-field-induced patterning of graphene heterostructures from the bottom interface creates an alternative architecture concept for their applications.
74 ATOMIC AND MOLECULAR PHYSICS↗
Anti-site defect-induced disorder in compensated topological magnet MnBi2-xSbxTe4
Abstract The gapped Dirac-like surface states of compensated magnetic topological insulator MnBi 2-x Sb x Te 4 (MBST) are a promising host for exotic quantum phenomena such as the quantum anomalous Hall effect and axion insulating state. However, it has become clear that atomic defects undermine the stabilization of such quantum phases as they lead to spatial variations in the surface state gap and doping levels. The large number of possible defect configurations in MBST make studying the influence of individual defects virtually impossible. Here, we present a statistical analysis of the nanoscale effect of defects in MBST with x =0.64, by scanning tunnelling microscopy/spectroscopy. We identify (Bi,Sb) Mn anti-site defects to be the main source of the observed doping fluctuations, leading towards the formation of nanoscale charge puddles and effectively closing the transport gap. Our findings will guide further optimization of this material system via defect engineering, to enable exploitation of its promising properties.
36 MATERIALS SCIENCE↗