Atomic structure and electronic transport properties of amorphous NaxSn1-xalloys

In this payer, we report on vapour-quenched NaxSn1-x films prepared in ultr a high vacuum at T approximate to 4 K. Measurements were performed in situ until crystallization. Just after condensation the samples had a structure factor with well-resolved first and second peaks. Over the complete range o f composition the latter is close to 2k(F), the scattering vector which cor responds to the diameter of the Fermi sphere. This correspondence indicates an affect of the conduction electrons on atomic structure as in Hume-Rothe ry phases or Peierls-systems. At medium compositions, a prepeak exists simi lar to the corresponding liquid state and the number density is approximate ly 50% higher than we expect with the assumption of constant atomic volumes of the constituents. Annealing causes structural changes within the amorph ous phase, accompanied by an increase of the resistivity a factor of less t han or equal to 1000. All these effects are explained by charge transfer an d clustering effects which are driven by the conduction electrons. (C) 1999 Elsevier Science B.V. All rights reserved.