<?xml version="1.0" encoding="utf-8"?>
<export-example>
  <doc>
    <id>16670</id>
    <completedYear/>
    <publishedYear>2014</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst>174506</pageFirst>
    <pageLast/>
    <pageNumber/>
    <edition/>
    <issue/>
    <volume>89</volume>
    <type>articler</type>
    <publisherName/>
    <publisherPlace/>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>2016-06-30</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">Optical excitation of phase modes in strongly disordered superconductors</title>
    <abstract language="eng">According to the Goldstone theorem the breaking of a continuous U(1) symmetry comes along with the existence of low-energy collective modes. In the context of superconductivity these excitations are related to the phase of the superconducting (SC) order parameter and for clean systems are optically inactive; that is, single-mode excitations do not directly couple to light. Here we show that for strongly disordered superconductors phase modes acquire a dipole moment and appear as a subgap spectral feature in the optical conductivity. This finding is obtained with both a gauge-invariant random-phase approximation scheme based on a fermionic Bogoliubov–de Gennes state and a prototypical bosonic model for disordered superconductors. In the strongly disordered regime, where the system displays an effective granularity of the SC properties, the optically active dipoles are linked to the isolated SC islands, offering a new perspective for realizing microwave optical devices.</abstract>
    <parentTitle language="eng">Physical Review B</parentTitle>
    <identifier type="doi">10.1103/PhysRevB.89.174506</identifier>
    <identifier type="url">http://journals.aps.org/prb/abstract/10.1103/PhysRevB.89.174506</identifier>
    <identifier type="issn">2469-9969</identifier>
    <enrichment key="BTU">nicht an der BTU erstellt / not created at BTU</enrichment>
    <author>
      <firstName>Tommaso</firstName>
      <lastName>Cea</lastName>
    </author>
    <submitter>
      <firstName>Katrin</firstName>
      <lastName>Gregor</lastName>
    </submitter>
    <author>
      <firstName>Daniel</firstName>
      <lastName>Bucheli</lastName>
    </author>
    <author>
      <firstName>Götz</firstName>
      <lastName>Seibold</lastName>
    </author>
    <author>
      <firstName>Lara</firstName>
      <lastName>Benfatto</lastName>
    </author>
    <author>
      <firstName>José</firstName>
      <lastName>Lorenzana</lastName>
    </author>
    <author>
      <firstName>Claudio</firstName>
      <lastName>Castellani</lastName>
    </author>
    <collection role="institutes" number="1501">FG Computational Physics</collection>
  </doc>
  <doc>
    <id>16672</id>
    <completedYear/>
    <publishedYear>2014</publishedYear>
    <thesisYearAccepted/>
    <language>eng</language>
    <pageFirst>5319</pageFirst>
    <pageLast/>
    <pageNumber/>
    <edition/>
    <issue>4</issue>
    <volume/>
    <type>articler</type>
    <publisherName/>
    <publisherPlace/>
    <creatingCorporation/>
    <contributingCorporation/>
    <belongsToBibliography>0</belongsToBibliography>
    <completedDate>2016-06-30</completedDate>
    <publishedDate>--</publishedDate>
    <thesisDateAccepted>--</thesisDateAccepted>
    <title language="eng">Spin excitations of ferronematic order in underdoped cuprate superconductors</title>
    <abstract language="eng">High-temperature superconductors exhibit a characteristic hourglass-shaped spectrum of magnetic fluctuations which most likely contribute to the pairing glue in the cuprates. Recent neutron scattering experiments in strongly underdoped compounds have revealed a significant low energy anisotropy of these fluctuations which we explain by a model in which topological defects of the antiferromagnet clump to producing domain wall segments with ferronematic order. This state does not invoke global charge order but breaks C4 rotational and inversion symmetry. The incommensurability of the low doping charge-disordered state is in good agreement with experiment and interpolates smoothly with the incommensurability of the stripe phase at higher doping. Within linear spin-wave theory the dynamic structure factor is in very good agreement with inelastic neutron scattering data and can account for the observed energy dependent anisotropy.</abstract>
    <parentTitle language="eng">Scientific reports</parentTitle>
    <identifier type="doi">10.1038/srep05319</identifier>
    <identifier type="url">http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4060504/</identifier>
    <identifier type="issn">2045-2322</identifier>
    <enrichment key="BTU">an der BTU erstellt / created at BTU</enrichment>
    <author>
      <firstName>Götz</firstName>
      <lastName>Seibold</lastName>
    </author>
    <submitter>
      <firstName>Katrin</firstName>
      <lastName>Gregor</lastName>
    </submitter>
    <author>
      <firstName>Carlo</firstName>
      <lastName>Di Castro</lastName>
    </author>
    <author>
      <firstName>Marco</firstName>
      <lastName>Grilli</lastName>
    </author>
    <author>
      <firstName>José</firstName>
      <lastName>Lorenzana</lastName>
    </author>
    <collection role="institutes" number="1501">FG Computational Physics</collection>
  </doc>
</export-example>
