Degeneracy in Intercalated Pb Phases under Buffer-Layer Graphene on SiC(0001) and Diffuse Moiré Spots in Surface Diffraction.

First-principles density functional theory (DFT) is used to analyze the stability of Pb intercalated phases under buffer layer graphene on SiC(0001) as a function of the supercell size, Pb coverage, and degree of Pb ordering. By comparing the chemical potentials of such two-dimensional Pb structures, we find that there is a family of structurally distinct thermodynamically preferred Pb subsurface configurations with minute stability differences. These differences are comparable to the thermal energies at about 450 °C, where the Pb intercalated phases are grown.

Breaking of Inversion Symmetry and Interlayer Electronic Coupling in Bilayer Graphene Heterostructure by Structural Implementation of High Electric Displacement Fields.

Controlling the interlayer coupling in two-dimensional (2D) materials generates novel electronic and topological phases. Its effective implementation is commonly done with a transverse electric field. However, phases generated by high displacement fields are elusive in this standard approach.

Thermodynamically Driven Formation of Intercalated Cu Carpets from Supported Cu Pyramids on MoS.

Thermodynamic and kinetic analyses based on our first-principles density functional theory calculations are used to interpret the experimentally observed formation of Cu carpets intercalated under the top layer of a 2-MoS substrate. Spontaneous Cu transport from Cu pyramids on top of the MoS substrate through surface point defects to the growing Cu carpet is shown to be driven by a slightly lower chemical potential for the Cu carpet. We demonstrate that the competition between a preference for a thicker Cu carpet and the cost of elastic stretching of the top MoS layer results in a selected Cu carpet thickness.

What the American Journal of Critical Care Junior Peer Reviewers Were Reading During the First Year of the Program: Caring for Patients With COVID-19.

The Junior Peer Reviewer program of the American Journal of Critical Care provides mentorship in the peer review process to novice reviewers. The program includes discussion sessions in which participants review articles published in other journals to practice and improve their critical appraisal skills. The articles reviewed during the first year of the program focused on caring for patients with COVID-19.