arXiv 1702.006432017-02-02cond-mat.supr-con

Exotic phase transition and superconductivity in layered titanium-oxypnictides implied by a computational phonon analysis

Kousuke Nakano, Kenta Hongo, Ryo Maezono

发表信息：: Inorg. Chem. 2017, 56, 22, 13732-13740
DOI：: 10.1021/acs.inorgchem.7b01709

英文摘要：

We applied $ab$ $initio$ phonon analysis to layered titanium-oxypnictides, Na$_2$Ti$_2Pn_2$O ($Pn$ = As, Sb), and found a clear contrast between the cases with lighter/heavier pnictogen in comparisons with experiments. The result completely explains the experimental structure, $C$2/$m$ for $Pn$ = As, within the conventional electron-phonon framework, while there arise discrepancies when the pnictogen gets heavier, being in the same trend for the BaTi$_2Pn_2$O ($Pn$ = As, Sb, Bi) case. The fact implies a systematic dependence on pnictogen to tune the mechanism of the phase transition and superconductivity from conventional to exotic.

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