Interfacial effects on the spin density wave in FeSe/SrTiO3thin films

Recently, the signs of both superconducting transition temperature (Tc) beyond 60 K and spin density wave (SDW) have been observed in FeSe thin film on SrTiO3 (STO) substrate, which suggests a strong interplay between superconductivity and magnetism. With the first-principles calculations, we find that the substrate-induced tensile strain tends to stabilize the SDW state in FeSe thin film by enhancing of the next-nearest-neighbor superexchange antiferromagnetic interaction bridged through Se atoms. On the other hand, we find that when there are oxygen vacancies in the substrate, the significant charge transfer from the substrate to the first FeSe layer would suppress the magnetic order there, and thus the high-temperature superconductivity could occur. In addition, the stability of the SDW is lowered when FeSe is on a defect-free STO substrate due to the redistribution of charges among the Fe 3d-orbitals. Our results provide a comprehensive microscopic explanation for the recent experimental findings, and build a foundation for the further exploration of the superconductivity and magnetism in this novel superconducting interface.

[1]  Xi Chen,et al.  Interface-Induced High-Temperature Superconductivity in Single Unit-Cell FeSe Films on SrTiO3 , 2012 .

[2]  Lin Zhao,et al.  Phase diagram and electronic indication of high-temperature superconductivity at 65 K in single-layer FeSe films. , 2012, Nature materials.

[3]  G. G. Stokes.  "J." , 1890, The New Yale Book of Quotations.

[4]  T. Xiang,et al.  Interface-induced superconductivity and strain-dependent spin density waves in FeSe/SrTiO3 thin films. , 2013, Nature materials.

[5]  Q. Xue,et al.  Molecular-beam epitaxy and robust superconductivity of stoichiometric FeSe crystalline films on bilayer graphene , 2011 .

[6]  Tersoff,et al.  Schottky barriers and semiconductor band structures. , 1985, Physical review. B, Condensed matter.

[7]  E. Tsymbal,et al.  Oxygen vacancies at titanate interfaces: Two-dimensional magnetism and orbital reconstruction , 2012, 1204.4711.

[8]  G. Scuseria,et al.  Modeling of the cubic and antiferrodistortive phases of SrTiO 3 with screened hybrid density functional theory , 2011, 1105.3353.

[9]  H. N. Lee,et al.  Oxygen-vacancy-induced orbital reconstruction of Ti ions at the interface of LaAlO3/SrTiO3 heterostructures: a resonant soft-X-ray scattering study. , 2013, Physical review letters.

[10]  John B. Goodenough,et al.  Theory of the role of covalence in the perovskite-type manganites [La,M(II)]MnO3 , 1955 .

[11]  Lin Zhao,et al.  Electronic origin of high-temperature superconductivity in single-layer FeSe superconductor , 2012, Nature Communications.

[12]  Scheffler,et al.  Adsorbate-substrate and adsorbate-adsorbate interactions of Na and K adlayers on Al(111). , 1992, Physical review. B, Condensed matter.

[13]  Zhong-Yi Lu,et al.  Iron-based layered compound LaFeAsO is an antiferromagnetic semimetal , 2008, 0803.3286.

[14]  G. Kresse,et al.  Efficiency of ab-initio total energy calculations for metals and semiconductors using a plane-wave basis set , 1996 .

[15]  David J. Singh,et al.  Density functional study of FeS, FeSe and FeTe: Electronic structure, magnetism, phonons and superconductivity , 2008, 0807.4312.

[16]  E. Tsymbal,et al.  Magnetic and superconducting phases at the LaAlO 3 /SrTiO 3 interface: The role of interfacial Ti 3 d electrons , 2012 .

[17]  Burke,et al.  Generalized Gradient Approximation Made Simple. , 1996, Physical review letters.

[18]  T. Xiang,et al.  First-principles calculations of the electronic structure of tetragonal alpha-FeTe and alpha-FeSe crystals: evidence for a bicollinear antiferromagnetic order. , 2009, Physical review letters.

[19]  Yi-Lin Huang,et al.  Superconductivity in the PbO-type structure α-FeSe , 2008, Proceedings of the National Academy of Sciences.

[20]  H. Monkhorst,et al.  SPECIAL POINTS FOR BRILLOUIN-ZONE INTEGRATIONS , 1976 .

[21]  T. Kopp,et al.  Two-dimensional electron liquid state at LaAlO 3 -SrTiO 3 interfaces , 2009, 0907.1176.

[22]  G. Kresse,et al.  From ultrasoft pseudopotentials to the projector augmented-wave method , 1999 .

[23]  Blöchl,et al.  Projector augmented-wave method. , 1994, Physical review. B, Condensed matter.

[24]  Tao Xiang,et al.  Atomic and electronic structures of FeSe monolayer and bilayer thin films on SrTiO3 (001): First-principles study , 2012 .

[25]  Xiangshan Chen,et al.  Atomic and electronic structures of single-layer FeSe on SrTiO3(001): The role of oxygen deficiency , 2013 .

[26]  G. Henkelman,et al.  A grid-based Bader analysis algorithm without lattice bias , 2009, Journal of physics. Condensed matter : an Institute of Physics journal.

[27]  T. Xiang,et al.  Arsenic-bridged antiferromagnetic superexchange interactions in LaFeAsO , 2008, 0804.3370.

[28]  Kresse,et al.  Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. , 1996, Physical review. B, Condensed matter.

[29]  W. Kang,et al.  Antiferromagnetic FeSe monolayer on SrTiO3: The charge doping and electric field effects , 2013, Scientific Reports.

[30]  Timur Bazhirov,et al.  Effects of charge doping and constrained magnetization on the electronic structure of an FeSe monolayer , 2012, Journal of physics. Condensed matter : an Institute of Physics journal.

[31]  Local antiferromagnetic exchange and collaborative Fermi surface as key ingredients of high temperature superconductors , 2011, Scientific reports.