Bulk electronic structure of Zn-Mg-Y and Zn-Mg-Dy icosahedral quasicrystals

Abstract

We use bulk sensitive hard x-ray photoelectron spectroscopy to provide unambiguous evidence for a pseudogap in the density of states around the Fermi level in icosahedral Zn-Mg-Y and Zn-Mg-Dy quasicrystals, in agreement with our density functional theory calculations. The pseudogap in these Zn-based quasicrystals is less pronounced compared to the Al-based ones such as Al-Pd-Mn and AlCu-Fe [J. Nayak et al., Phys. Rev. Lett. 109, 216403 (2012)]. This observation is in agreement with transport studies that indicate a larger charge carrier concentration in the Zn-based quasicrystals. Compared to Zn-Mg-Dy, the pseudogap is somewhat deeper in Zn-Mg-Y. The larger width of the Mg 1s and Zn 2p core-level spectra in Zn-Mg-Y is explained by different configurations of the local atomic surrounding compared to Zn-Mg-Dy.

High Performance of Manganese Porphyrin Sensitized p-Type CuFe2O4 Photocathode for Solar Water Splitting to Produce Hydrogen in a Tandem Photoelectrochemical Cell

“…These results are consistent with that of the CuFe 2 O 4 nanospheres prepared by the reported hydrothermal method [28]. The Cu 2p peaks' intensity and the width of the MnTPP/CuFe 2 O 4 showed a decrease compared to CuFe 2 O 4 , which may attributed to a decrease of the content and the number of inequivalent sites of Cu on the composite's surface when increasing the MnTPP ratio in the composite [29,30]. In addition, a negative shift or a smaller peak binding energy is observed for both Fe 2p and Cu 2p peaks in the XPS spectra of the MnTPP/CuFe 2 O 4 sample, this result shows the formation of new chemical bonds after combining MnTPP with CuFe 2 O 4 , demonstrating that there is an interaction between MnTPP and CuFe 2 O 4 in the nanohybrid [31].…”

Electronic structure of β−Al3Mg2 and Al13Fe4<

“…Thus, unlike high-order approximants [38] or quasicrystals [19,37,63], the near-E F HAXPES spectrum of β-Al 3 Mg 2 shows a well developed metallic Fermi edge. This is consistent with its metallic resistivity (33.2 µΩ cm at 4 K [6]) with a positive temperature coefficient, showing the dominance of electron-phonon interactions as in a metal [6].…”

“…[a ′ √ (E − b ′ )]. Such an approach has been used earlier for related systems such as high order approximants [38] and quasicrystals [19,35,37,65]. The expression used for fitting is given by […”

“…In recent years, HAXPES has been used to study the bulk electronic structure of quasicrystalline and related materials. Among the important findings by HAXPES are the evidence of Anderson localization in i-Al-Pd-Re [35], heterogeneous valence states in Yb-based quasicrystalline approximants [36], and pseudogap around E F in different icosahedral quasicrystals [19,35,37] and high-order approximants [38] have been reported. HAXPES uses photons in the range of 6-8 keV, and thus the inelastic mean free path of the photoelectrons increases to 6-10 nm [39].…”

Fermi states and anisotropy of Brillouin zone scattering in the decagonal Al–Ni–Co quasicrystal

“…These questions have been explored in a number of theoretical articles 4 5 6 7 8 9 10 11 and experimental works 12 13 14 15 16 17 18 19 . Angle-resolved photoemission spectroscopy (ARPES) experiments utilizing vacuum ultraviolet (VUV) radiation established the general electronic structure of d-AlNiCo, showing that in the binding energy E b range far from E F the Al sp -derived states have clear dispersive character and hence are effectively delocalized 20 21 .…”