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arXiv 1107.0409cond-mat.supr-con
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超导K0.8Fe 1.6Se 2(Tc= 31.8 K)单晶的本征相分离

Intrinsic phase separation in superconducting K0.8Fe1.6Se2 (Tc= 31.8 K) single crystals

Alessandro Ricci, Nicola Poccia, Boby Joseph, Gianmichele Arrighetti, Luisa Barba, Jasper Plaisier, Gaetano Campi, Yoshikazu Mizuguchi, Hiroyuki Takeya, Yoshihi… 展开作者

Alessandro Ricci, Nicola Poccia, Boby Joseph, Gianmichele Arrighetti, Luisa Barba, Jasper Plaisier, Gaetano Campi, Yoshikazu Mizuguchi, Hiroyuki Takeya, Yoshihiko Takano, Naurang Lal Saini, Antonio Bianconi

摘要:

本文报道了用同步辐射对新发现的K_(0.8)Fe_(1.6)Se_2超导体(Tc = 31.8 K)进行的变温X射线衍射(XRD)研究。一个明确的证据,在520 K的内在相分离之间的两个竞争相,(i)第一个多数磁性相与ThCr 2Si 2型四相晶格调制的铁空位排序和(ii)少数非磁性相具有面内压缩晶格体积和弱超结构,报告。XRD峰由于Fe空位有序在大多数相消失,通过增加温度在580 K,远高于相分离温度,确认有序-无序相变。在520 K下,在具有晶格超结构的正相中竞争的第一磁性相和第二非磁性相之间的本征相分离(这意味着不同的费米表面拓扑结构重建和电荷密度)被分配给晶格电子不稳定性的K0.8Fe1.6Se2系统典型的系统调谐在一个电子拓扑转变的Lifshitz临界点,给出了一个多-间隙超导体调谐形状共振。

英文摘要:

Temperature dependent single-crystal x-ray diffraction (XRD) in transmission mode probing the bulk of the newly discovered K0.8Fe1.6Se2 superconductor (Tc = 31.8 K) using synchrotron radiation is reported. A clear evidence of intrinsic phase separation at 520 K between two competing phases, (i) a first majority magnetic phase with a ThCr2Si2-type tetragonal lattice modulated by the iron vacancy ordering and (ii) a minority non-magnetic phase having an in-plane compressed lattice volume and a weak superstructure, is reported. The XRD peaks due to the Fe vacancy ordering in the majority phase disappear by increasing the temperature at 580 K, well above phase separation temperature confirming the order-disorder phase transition. The intrinsic phase separation at 520K between a competing first magnetic phase and a second non-magnetic phase in the normal phase both having lattice superstructures (that imply different Fermi surface topology reconstruction and charge density) is assigned to a lattice-electronic instability of the K0.8Fe1.6Se2 system typical of a system tuned at a Lifshitz critical point of an electronic topological transition that gives a multi-gaps superconductor tuned a shape resonance.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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