Abstract

The Charge Density Wave (CDW) in ZrTe_3 is driven by a Fermi-surface nesting of the quasi 1-dimensional Fermi surface sheet of the Te p_x orbitals. The layered material is made of prismatic ZrTe_3 chains that are laterally linked through Te p-bonding. The CDW develops below T_CDW = 63 K with a modulation vector q_CDW in the a-c-plane perpendicular to the prismatic chains.

In this seminar I will present lattice dynamics data from inelastic x-ray scattering (IXS) that show the soft mode mechanism of the charge density wave and reveal the thermodynamics of the phase transition far from mean field behaviour. A set of high resolution angle resolved photoemission (ARPES) data shows the opening of a gap in the Fermi surface and allows the determination of its magnitude.

A comparison of the observed electron dispersions with a first principles calculation shows that the surface sensitive ARPES is not compatible with the expected bulk electronic structure. Rather, the surface relaxation gives rise to a subtly modified behaviour in the top layer. This leads to the interesting conclusion that controlled modifications of the CDW system are possible at the surface and their properties can be studied by surface sensitive techniques.