Monoelemental 2D materials

Borophene grown under suitable conditions can have phase intermixing, with line defects in each phase adopting the unit structure of the other phase. Such 1D defects self-assemble into 2D periodic arrays, constituting new phases of borophene.

Low-energy electron microscopy enables controlled synthesis and characterization of (large) single-crystal borophene on metal substrates.

This Perspective discusses recent progress and future opportunities for borophene research.

A flat stanene layer can be grown on Cu (111) by MBE growth, exhibiting topological properties as revealed by a combination of ARPES, STM and DFT calculations.

Stanene is a single sheet of tin atoms. Here, it is shown that a few stacked layers of stanene can be a superconductor. Changing the thickness of the substrate modifies the form of superconductivity and critical temperature.

Scanning tunnelling microscopy and spectroscopy study of the conductive edge state in a two-dimensional topological insulator reveals the interplay of topology and electronic correlations.

Black phosphorus is being considered for energy storage but its rate and cycling capabilities are limited by intrinsic (de-)alloying. Molecular-level surface redox sites on oxidized black phosphorus can now be coupled with graphene via strong interlayer bonding.

Anisotropic honeycomb crystal of black phosphorous is found to have pseudospin polarization greater than 95% at room temperature, attributed to the merging of Dirac cones. This bipolar pseudospin semiconductor may be useful for pseudospintronics.

Tunnel field-effect transistors with spatially varying layer thickness in black phosphorus enable high performance with a record-low subthreshold swing.

The accidental band-crossing origin of Weyl nodes paired with the absence of sizeable band gaps hampers the exploitation of low-energy relativistic quasiparticles in Weyl semimetals. In a gate-tunable high-quality tellurene film, quantum Hall measurements unveil a topologically non-trivial π Berry phase caused by unconventional Weyl nodes in these tellurium two-dimensional sheets.