"The Bi1-
xSb
x single-crystal samples (0 ≤
x ≤ 0.17) used for ARPES experiments were each cleaved from a boule grown from a stoichiometric mixture of high-purity elements. The boule was cooled from 650 °C to 270 °C over a period of five days and was annealed for seven days at 270 °C.
The samples naturally cleaved along the (111) plane, which resulted in shiny flat silver surfaces. (bold - sic.) X-ray diffraction measurements were used to check that the samples were single phase, and confirmed that the Bi0.9Sb0.1 single crystals presented in this paper have a rhombohedral A7 crystal structure (point group
R
m), with room-temperature (300 K) lattice parameters
a = 4.51 Å and
c = 11.78 Å indexed using a rhombohedral unit cell. The X-ray diffraction patterns of the cleaved crystals exhibit only the (333), (666), and (999) peaks, showing that the cleaved surface is oriented along the trigonal (111) axis. Room-temperature data were recorded on a Bruker D8 diffractometer using Cu Kα radiation (λ = 1.54 Å) and a diffracted-beam monochromator. The in-plane crystal orientation was determined by Laue X-ray diffraction. During the angle-resolved photoemission spectroscopy (ARPES) measurements a fine alignment was achieved by carefully studying the band dispersions and Fermi surface symmetry as an internal check for crystal orientation. "
Hsieh, D., Qian, D., Wray, L.
et al. A topological Dirac insulator in a quantum spin Hall phase.
Nature 452, 970–974 (2008) doi:10.1038/nature06843
So Bi0.9Sb0.1 does exist at room temp. Bi has different surface structure than bulk (center). Pressure (expansion due to being in a containing mould) does change the structure a bit. The graph I posted did show a solid of Sb2Sn3.
As the Fiver's 'coring' theory, maybe? But to have Sn,SbSn, BiSb,etc primarily at the surface, something besides cooling must cause migration of molecules in the liquid. Some work has been done in solidus in a magnetic field. Yea, right.