Electronic Properties of the Linear Chain Mercury Compounds

Abstract

<p>The Fermi surface, resistivity and superconducting properties of the mercury linear chain compounds were studied.</p> <p>A detailed model of the Fermi surface of the mercury linear chain compounds has been constructed. Measurements of the dHvA frequencies in Hg₃₋δSbF₆ are presented and show that the Fermi surface of this compound consists of cylinders. The cross-sectional areas of these cylinders are accounted for by the Fermi surface model. Measurements of the dHvA frequencies in the Hg₃-δAsF₆ under pressures between 0 and 4 kbar are also presented. The changes in frequencies with pressure imply that the anions' lattice contracts while the mercury-mercury distance remains unchanged when the pressure is applied.</p> <p>A model of the lattice resistivity in these compounds is introduced and compared to our measurements of the resistivity between 4.2 and 90 K, and to measurements of the resistivity anisotropy between 4.2 and 250 K. A sudden resistance increase at 217 K, when the samples are cooled, is reported and is associated with mercury extrusion at the same temperature.</p> <p>Measurements of the ac susceptibility in Hg₃₋δAsF₆ for fields between 0 and 400 Gauss at temperatures of 4.2 to 1.2 K are reported. Transitions associated with elemental mercury and with the linear chain mercury compound are observed. The presence of elemental mercury with the compound is discussed. Measured values for the critical field, the critical temperature and the zero-field susceptibility of the mercury compound are presented and two explanations for these and previous results are suggested.</p>