Self-assembly of nanoscale lateral segregation profiles

Article

关键词: TOTAL-ENERGY CALCULATIONS;    HEXAGONAL BORON-NITRIDE;    SURFACE SEGREGATION;    SINGLE-LAYER;    H-BN;    ATOMS;   

DOI  :  10.1103/PhysRevB.93.161402

来源: SCIE

【 摘 要 】

The surface segregation profile of an intermetallic compound becomes vertically and laterally modulated upon epitaxial growth of a single-layer hexagonal boron nitride (h-BN) nanomesh. h-BN on PtRh(111) forms an 11-on-10 superhoneycomb, such as that on Rh(111) [Corso et al., Science 303, 217 (2004)], though with a smaller lattice constant of 2.73 nm. X-ray photoelectron diffraction shows that the h-BN layer reduces the Pt enrichment of the first layer by promoting site swapping of about 10 Pt-Rh pairs within the 10 x 10 unit cell between the first and second layers. This segregation profile is confirmed by density-functional-theory-based cluster-expansion calculations. Generally, a strong modulation of the h-BN bonding strength and a higher affinity to one of the constituents leads to self-assembly of top layer patches underneath the nanomesh pores.

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