Dresden 2011 – wissenschaftliches Programm
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TT: Fachverband Tiefe Temperaturen
TT 3: CE: Charge Density Wave \& Peierls Instability
TT 3.4: Vortrag
Montag, 14. März 2011, 11:15–11:30, HSZ 304
The role of charge order in the layered superconducter NbSe2 — •Dirk Rahn1, Stefan Hellmann1, Christian Sohrt1, Matthias Kalläne1, Timur Kim2, Bernd Büchner2, Lutz Kipp1, and Kai Rossnagel1 — 1Institut für Experimentelle und Angewandte Physik, Universität Kiel, Germany — 2IFW Dresden, Germany
The layered compound 2H-NbSe2 has emerged from a prototype BCS like superconductor to a material with a coexistence of charge-density waves (CDW) and superconductivity (SC) at low temperatures. These two phenomena have led to strong controversity about the symmetry of the gap function [1] and the nature of the interplay between them.
Due to the analogy with the high-Tc cuprates, recent ARPES studies of the near-EF electronic structure [2,3] tried to unveil the gap symmetry as well as the role of the CDW in SC. These studies end up with a contradiction between CDW enhanced and CDW weakened SC and with an uncertainty in the gap symmetry because the measurements were done at T > Tc/2.
We present a comprehensive ARPES study of the momentum-resolved near-EF electronic sturcture at T ≈ 1 K. This allows us to determine the parts of the Fermi surface that stabilize the CDW as well as those parts that are gapped by SC. Furthermore, we see clear fingerprints of different phonon modes in the spectra, which enables us to reveal the correlation between SC, CDW, and the different parts of the phonon spectrum.
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