Experimental and theoretical study of the electronic structure of $\mathrm{Au}{\mathrm{Al}}_2$, $\mathrm{Au}{\mathrm{Ga}}_2$, and $\mathrm{Au}{\mathrm{In}}_2$

The binding energies of the Au $5d$ bands at the $\Gamma$ point for $\mathrm{Au}{\mathrm{Al}}_2$, $\mathrm{Au}{\mathrm{Ga}}_2$, and $\mathrm{Au}{\mathrm{In}}_2$ calculated from the first-principles theory agree with those obtained from the angle-integrated or angle-resolved photoemission spectroscopic study to within 10%. X-ray absorption near-edge spectroscopy (XANES) spectra of these three compounds are presented and compared with theoretical XANES spectra and site- and momentum-decomposed partial density of states. Extended x-ray absorption fine structure spectra of $\mathrm{Au}{\mathrm{Al}}_2$, $\mathrm{Au}{\mathrm{Ga}}_2$, and $\mathrm{Au}{\mathrm{In}}_2$ are also analyzed to yield the bonding parameters.

Figure 1

The Au $L_3$-edge XANES spectra for (a) $\mathrm{Au}{\mathrm{Al}}_2$, (b) $\mathrm{Au}{\mathrm{Ga}}_2$, and (c) $\mathrm{Au}{\mathrm{In}}_2$.

Figure 2

The Ga $K$-edge XANES spectra for $\mathrm{Au}{\mathrm{Ga}}_2$.

Figure 3

The In (a) $L_3$-edge and (b) $K$-edge XANES spectra for $\mathrm{Au}{\mathrm{In}}_2$.

Figure 4

(Color online) The experimental (solid lines) and the theoretical fitted (open circles) Fourier transforms of $k^3$-weighted Au $L_3$-edge EXAFS spectra for $\mathrm{Au}{\mathrm{Al}}_2$.