Avoided Quantum Criticality and Magnetoelastic Coupling in BaFe2-xNixAs2
Avoided Quantum Criticality and Magnetoelastic Coupling in BaFe2-xNixAs2
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BaFe2-xNixAs2 中避免的量子临界和磁弹性耦合
DOI：
10.1103/physrevlett.110.257001
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发表时间：
2013-06-18
影响因子：
8.6
通讯作者：
Dai, Pengcheng
中科院分区：
文献类型：
--
作者：
Lu, Xingye;Gretarsson, H.;Dai, Pengcheng
利用高分辨同步辐射X射线和中子散射研究了电子掺杂BaFe_（2-x）Ni_xAs_2的结构和磁性有序。当Ni掺杂x时，BaFe_2As_2中几乎同时发生的四方晶到正交晶（T-s）和反铁磁（T-N）相变逐渐被抑制和分离，导致T-s > T-N随着x的增加，如先前观察到的。当x >= 0.065时，Ts和T-N之间的温度间隔随x的增大而减小，并趋向于在x接近0.1时接近最佳超导性的量子双临界点。在0：088小于或近似于x小于或近似于0.104的区域中，零温转变被第二无公度磁相的形成所抢先，导致在超导圆顶上方x近似于0.1的T-N的有限值近似于T-c + 10 K。我们的结果意味着避免量子临界点，这是预计将强烈影响正常和超导状态的属性。
We study the structural and magnetic orders in electron-doped BaFe2-xNixAs2 by high-resolution synchrotron x-ray and neutron scatterings. Upon Ni doping x, the nearly simultaneous tetragonal-to-orthorhombic structural (T-s) and antiferromagnetic (T-N) phase transitions in BaFe2As2 are gradually suppressed and separated, resulting in T-s > T-N with increasing x, as was previously observed. However, the temperature separation between T-s and T-N decreases with increasing x for x >= 0.065, tending toward a quantum bicritical point near optimal superconductivity at x approximate to 0.1. The zero-temperature transition is preempted by the formation of a secondary incommensurate magnetic phase in the region 0: 088 less than or similar to x less than or similar to 0.104, resulting in a finite value of T-N approximate to T-c + 10 K above the superconducting dome around x approximate to 0.1. Our results imply an avoided quantum critical point, which is expected to strongly influence the properties of both the normal and superconducting states.