A site-selective antiferromagnetic ground state in layered pnictide-oxide BaTi2As2O

Yu, Xiang-Long; Liu, Dayong; Quan, Ya‐Min; Jia, Ting; Lin, Hai‐Qing; Zou, Liang‐Jian

doi:10.1063/1.4866701

Cited by 12 publications

(11 citation statements)

References 11 publications

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“…Due to the Fermi surface (FS) nesting, the AFM fluctuations develop at Q s = (π, 0, π) and (0, π, π), consistently with the previous theoretical studies [28,29] and the NMR study [22]. Remarkably, we find that the strong orbital fluctuations at q = (0, 0, 0) are induced by the Aslamazov-Larkin vertex correction (AL-VC), which is neglected in the RPA.…”

Section: Introductionsupporting

confidence: 61%

Theoretical prediction of nematic orbital-ordered state in the Ti oxypnictide superconductorBaTi2(As,Sb)2O

2016

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The electronic nematic state without magnetization emerges in various strongly correlated metals such as Fe-based and cuprate superconductors. To understand this universal phenomenon, we focus on the nematic state in Ti-oxypnictide BaTi2(As,Sb)2O, which is expressed as the threedimensional 10-orbital Hubbard model. The antiferromagnetic fluctuations are caused by the Fermi surface nesting. Interestingly, we find the spin-fluctuation-driven orbital order due to the strong orbital-spin interference, which is described by the Aslamazov-Larkin vertex correction (AL-VC). The predicted intra-unit-cell nematic orbital order is consistent with the recent experimental reports on BaTi2(As,Sb)2O. Thus, the spin-fluctuation-driven orbital order due to the AL-VC mechanism is expected to be universal in various two-and three-dimensional multiorbital metals.

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Section: Introductionsupporting

confidence: 61%

Theoretical prediction of nematic orbital-ordered state in the Ti oxypnictide superconductorBaTi2(As,Sb)2O

2016

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“…[27][28][29][30][31] Many attempts have been made to identify the DW phase in the titanium oxypnictides. Electronic structure models predict a highly anisotropic Fermi surface with box-like electron and hole pockets that are quite well nested and therefore susceptible to either SDW or CDW instabilities [32][33][34][35][36][37][38] . The calculations indicate that strong electron-phonon coupling could induce a superlattice distortion and accompanying CDW.…”

Section: Introductionmentioning

confidence: 99%

Coupled commensurate charge density wave and lattice distortion inNa2Ti2Pn2O(Pn=As,

et al. 2016

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We report single crystal X-ray diffraction measurements on Na2Ti2P n2O (P n = As, Sb) which reveal a charge superstructure that appears below the density wave transitions previously observed in bulk data. From symmetry-constrained structure refinements we establish that the associated distortion mode can be described by two propagation vectors, q1 = (1/2, 0, l) and q2 = (0, 1/2, l), with l = 0 (Sb) or l = 1/2 (As), and primarily involves in-plane displacements of the Ti atoms perpendicular to the Ti-O bonds. We also present angle resolved photoemission spectroscopy (ARPES) measurements, which show band folding and back bending consistent with a density wave with the same wave vectors q1 and q2 associated with fermi surface nesting, and muon-spin relaxation data, which show no indication of spin density wave order. The results provide direct evidence for phononassisted charge density wave order in Na2Ti2P n2O and fully characterise a proximate ordered phase that could compete with superconductivity in doped BaTi2Sb2O.

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“…Anomalies in the temperature dependence of resistivity ρ(T ) and magnetic susceptibility χ(T ) at low temperature are sometimes observed in these systems, getting into an argument over if the anomalies can be attributed to the emergence of charge density waves (CDW) or spin density waves (SDW). [1,2,[4][5][6] Several DFT studies applied to BaTi 2 As 2 O and BaTi 2 Sb 2 O [21][22][23] have reported the possibility of SDW, while it has not yet been observed experimentally, such as by NMR/NQR for Sb 121/123 and µSR for BaTi 2 As 2 O and BaTi 2 Sb 2 O. [16][17][18] Focusing on CDW, the nesting of Fermi surface matters, which is enhanced by 2D nature of Ti 2 O planes.…”

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confidence: 99%

Phonon dispersions and Fermi surfaces nesting explaining the variety of charge ordering in titanium-oxypnictides superconductors

Nakano

Hongo

2016

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There has been a puzzle between experiments and theoretical predictions on the charge ordering of layered titanium-oxypnictides superconductors. Unconventional mechanisms to explain this discrepancy have been argued so far, even affecting the understanding of superconductivity on the compound. We provide a new theoretical prediction, by which the discrepancy itself is resolved without any complicated unconventional explanation. Phonon dispersions and changes of nesting vectors in Fermi surfaces are clarified to lead to the variety of superlattice structures even for the common crystal structures when without CDW, including orthorhombic 2 × 2 × 1 one for BaTi2As2O, which has not yet been explained successfully so far, being different from tetragonal for BaTi2Sb2O and BaTi2Bi2O. The electronic structure analysis can naturally explain experimental observations about CDW including most latest ones without any cramped unconventional mechanisms.

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A site-selective antiferromagnetic ground state in layered pnictide-oxide BaTi2As2O

Cited by 12 publications

References 11 publications

Theoretical prediction of nematic orbital-ordered state in the Ti oxypnictide superconductorBaTi2(As,Sb)2O

Theoretical prediction of nematic orbital-ordered state in the Ti oxypnictide superconductorBaTi2(As,Sb)2O

Coupled commensurate charge density wave and lattice distortion inNa2Ti2Pn2O(Pn=As,

Phonon dispersions and Fermi surfaces nesting explaining the variety of charge ordering in titanium-oxypnictides superconductors

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