Discovery of Hexagonal Structured Pd-B Nanocrystals.

We report on hexagonal close-packed (hcp) palladium (Pd)-boron (B) nanocrystals (NCs) by heavy B doping into face-centered cubic (fcc) Pd NCs. Scanning transmission electron microscopy-electron energy loss spectroscopy and synchrotron powder X-ray diffraction measurements demonstrated that the B atoms are homogeneously distributed inside the hcp Pd lattice. The large paramagnetic susceptibility of Pd is significantly suppressed in Pd-B NCs in good agreement with the reduction of density of states at Fermi energy suggested by X-ray absorption near-edge structure and theoretical calculations.