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@ARTICLE{Yamauchi:62807,
      author       = {Yamauchi, K. and Freimuth, F. and Blügel, S. and Picozzi,
                      S.},
      title        = {{M}agnetically induced ferroelectricity in orthorhombic
                      manganites: {M}icroscopic origin and chemical trends},
      journal      = {Physical review / B},
      volume       = {78},
      number       = {1},
      issn         = {1098-0121},
      address      = {College Park, Md.},
      publisher    = {APS},
      reportid     = {PreJuSER-62807},
      pages        = {014403},
      year         = {2008},
      note         = {Record converted from VDB: 12.11.2012},
      abstract     = {The microscopic origin of the magnetically driven
                      ferroelectricity in collinear E-type antiferromagnetic
                      (AFM-E) orthorhombic manganites is explained by means of
                      first-principles Wannier functions. We show that the
                      polarization is mainly determined by the asymmetric electron
                      hopping of orbitally polarized e(g) states, implicit in the
                      peculiar in-plane zigzag spin arrangement in the AFM-E
                      configuration. In ortho-HoMnO3, Wannier-function centers are
                      largely displaced with respect to corresponding ionic
                      positions, implying that the final polarization is strongly
                      affected by a purely electronic contribution, at variance
                      with standard ferroelectrics where the ionic displacement is
                      dominant. However, the final value of the polarization is
                      the result of competing effects, as shown by the opposite
                      signs of the contributions to the polarization coming from
                      the Mn e(g) and t(2g) states. Furthermore, a systematic
                      analysis of the link between ferroelectricity and the spin,
                      orbital, and lattice degrees of freedom in the manganite
                      series has been carried out, in the aim of ascertaining
                      chemical trends as a function of the rare-earth ion. Our
                      results show that the Mn-O-Mn angle is the key quantity in
                      determining the exchange coupling: upon decreasing the
                      Mn-O-Mn angle, the first- (second-) nearest-neighbor
                      ferromagnetic (antiferromagnetic) interaction decreases
                      (remains constant), in turn stabilizing either the A-type
                      antiferromagnetic or the AFM-E spin configuration for weakly
                      or strongly distorted manganites, respectively. The Mn e(g)
                      contribution to the polarization dramatically increases with
                      the Mn-O-Mn angle and decreases with the "long" Mn-O bond
                      length, whereas the Mn t(2g) contribution decreases with the
                      "short" Mn-O bond length, partially canceling the former
                      term.},
      keywords     = {J (WoSType)},
      cin          = {CNI / IFF-1 / JARA-FIT / JARA-SIM},
      ddc          = {530},
      cid          = {I:(DE-Juel1)VDB381 / I:(DE-Juel1)VDB781 /
                      $I:(DE-82)080009_20140620$ / I:(DE-Juel1)VDB1045},
      pnm          = {Grundlagen für zukünftige Informationstechnologien},
      pid          = {G:(DE-Juel1)FUEK412},
      shelfmark    = {Physics, Condensed Matter},
      typ          = {PUB:(DE-HGF)16},
      UT           = {WOS:000258190000062},
      doi          = {10.1103/PhysRevB.78.014403},
      url          = {https://juser.fz-juelich.de/record/62807},
}