Some possibilities for laboratory searches for variations of fundamental constants

We consider different options for the search for possible variations of the fundamental constants. We give a brief overview of the results obtained with several methods. We discuss their advantages and disadvantages with respect to simultaneous variations of all constants in both time and space in the range 108–1010 years. We also suggest a few possibilities for the laboratory search. Particularly, we propose some experiments with the hyperfine structure of hydrogen, deuterium, and ytterbium–171 and of some atoms with a small magnetic moment. Other suggestions are for some measurements of the fine structure associated with the ground state. Special attention is paid to the interpretation of the hfs measurements in terms of variations of the fundamental constants. PACS No.: 31.30G

Electronic Structure of Pd doped InP

ABSTRACTThe electronic structure of metal impurities in III-V semiconductors are interesting because of their ability to create deep centers. We use a spin unrestricted self-consistent local density theory in a cluster model to calculate the charge distributions, one electron energy spectra and the density of states for pure InP and Pd doped InP, substituted at the In site. The pure semiconductor gap is calculated to be 1.44 eV in excellent agreement with the experimental value of 1.41 eV. A small magnetic moment of 0.561μB appears on the Pd site. The impurity introduces a levels of t2 character at 0.01 and 0.04 eV above the valence band edge.

Multilayer Fe/Cu Films

ABSTRACTMultilayer films consisting of alternating Fe and Cu thin films have been made by a twin-gun sputtering device with a rotating substrate platform. Both proportional modulated films and films with a fixed Cu layer have been fabricated, where the Fe layer has been varied between 10 and 150 Å. These films have been studied by x-ray diffraction, Mö;ssbauer spectroscopy and SQUID magnetometry. Thin Fe layers with thicknesses less than 25 Å, exist only as fee α-Fe. Thicker Fe layers contain both bec and fee Fe. The interface between Fe and Cu appears very sharp with no evidence of Fe-Cu alloys. The α-Fe state orders magnetically below 100 K with a small magnetic moment.