Atomic and Electronic States of Ag in Sputter-Deposited Ge–Ag Alloys Studied by Photoemission Spectroscopy and Cluster Calculation

Abstract

For the observation of the charging effect on a Josephson junction, the charging energy (E c ) must be much larger than the Josephson coupling energy (E J ) and thermal energy (k B T). We investigated the properties of submicron-sized Bi 2 Sr 2 CaCu 2 O 8þ intrinsic Josephson junctions (IJJs) at low temperature. The current-voltage curve of IJJs with a junction area of 0.06 mm 2 showed a much higher resistance state near the zero bias voltage regions when the measurement temperature decreased to 72.6 mK. The ratios of E c =E J and E c =k B T were 7.04 and 5.78, respectively, which indicates that the charging effect is dominant. In addition, a characteristic voltage structure due to the charging effect in one-dimensional junction array, which is composed of the offset voltage and the threshold voltage of the junction, was observed.

Electronic Structure and Electrical Conductivity of Amorphous Si–Ti Alloys Manifesting the Metal-Insulator Transition

“…25) The calculation has been performed by the DV-Xα molecular orbital method in a similar way as described elsewhere. 18,20) Figure 8 shows the model cluster of Si 35 used for the calculation, where thirty-five Si atoms are arranged in diamond structure together with thirty-six H atoms added to terminate the surface dangling bonds. This cluster is larger in size than the Ge 17 cluster employed in the previous calculations.…”

“…This cluster is larger in size than the Ge 17 cluster employed in the previous calculations. 18,20) The alloy clusters, Si 34 Ti, Si 33 Ti 2 , Si 31 Ti 4 and Si 30 Ti 5 , are obtained by substituting the respective number of Ti atoms for the central, two 1st-neighbor, four 1st-neighbor, and the central plus four 1st-neighbor Si atoms, respectively. The interatomic distances, d Si-Si = 0.235 nm and d Si-H = 0.146 nm, are taken to be consistent with those of Si crystal and SiH 4 molecule, respectively.…”

“…[16][17][18][19] Briefly, a composite target of high-purity Si and 99.9% Ti chips of appropriate area ratio was simultaneously sputtered and deposited on a Si(111) or a quartz glass substrate to a film thickness of about 1 μm at ambient temperature. The former was used samples for photoemission study and the latter for electrical conductivity measurements.…”

“…This transition, called Anderson transition, has long been investigated for a variety of alloy systems and its mechanisms have been theoretically explored. [12][13][14][15] We have investigated the MIT effects in amorphous Si-Pd, 16) Si-Ni, 17) Ge-Ag 18) and GePd 19,20) alloys, and related them with the bandstructure or bonding characteristics of the alloys as revealed by photoemission spectroscopy. The reason for choosing the Si-Ti system in this study is as follows.…”

Density functional study of Ag n −1 Y ( n = 2–10) clusters

“…Willey et al [16] studied the photochemistry properties of ion-molecule complexes containing silver clusters. Suzuki and Tanaka [17] investigated the electronic structures of Ge-Ag alloy clusters with the DV-Xα method. Negishi et al [18] and Mitrić et al [19] investigated the photoelectron spectra of gold-silver binary clusters experimentally and theoretically, respectively.…”