Disorder Quenching of the Charge Density Wave in ZrTe3

The charge density wave (CDW) in ZrTe3 is quenched in samples with small amount of Te iso-electronically substituted by Se. Using angle-resolved photoemission spectroscopy we observe subtle changes in the electronic band dispersions and Fermi surfaces on Se substitution. The scattering rates are substantially increased, in particular for the large three-dimensional Fermi surface sheet. The quasi-one-dimensional band is unaffected by the substitution and still shows a gap at low temperature, which starts to open from room temperature. The detailed temperature dependence reveals that the long-range order is absent in the electronic states as in the periodic lattice distortion. The competition between superconductivity and CDW is thus linked to the suppression of long-range order of the CDW.