Quantum dynamics of hydrogen in the iron-based superconductor LaFeAsO0.9D0.1 measured with inelastic neutron spectroscopy
Quantum dynamics of hydrogen in the iron-based superconductor LaFeAsO0.9D0.1 measured with inelastic neutron spectroscopy
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DOI：
10.1103/physrevb.99.220505
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发表时间：
2019-05
影响因子：
3.7
通讯作者：
J. Yamaura;H. Hiraka;S. Iimura;Y. Muraba;J. Bang;K. Ikeuchi;M. Nakamura;Y. Inamura;T. Honda;M. Hiraishi;K. Kojima;R. Kadono;Y. Kuramoto;Y. Murakami;S. Matsuishi;H. Hosono
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作者：
J. Yamaura;H. Hiraka;S. Iimura;Y. Muraba;J. Bang;K. Ikeuchi;M. Nakamura;Y. Inamura;T. Honda;M. Hiraishi;K. Kojima;R. Kadono;Y. Kuramoto;Y. Murakami;S. Matsuishi;H. Hosono
对铁基超导体 LaFeAsO0.9D0.1 进行了非弹性中子散射，其中大部分 D（氘）取代了氧，而少量进入了间隙位置。通过第一性原理计算，我们用四个等效的潜在最小值来表征 D（以及稍微混合的 H）的间隙位点。低于超导转变温度 Tc = 26 K，新的激发出现在 5-15 meV 范围内，而它们在参考系统 LaFeAsO0.9F0.1 中不存在。 14.5 meV 和 11.1 meV 的强激发分别在 15 K 和 20 K 附近快速展宽，其中每个能量变得相当于超导能隙的两倍。强激发归因于量子震颤或氢的带运动，只有当潜在最小值的数量大于二时才会出现。
Inelastic neutron scattering was performed for an iron-based superconductor LaFeAsO0.9D0.1, where most of D (deuterium) replaces oxygen, while a tiny amount goes into interstitial sites. By first-principle calculation, we characterize the interstitial sites for D (and for H slightly mixed) with four equivalent potential minima. Below the superconducting transition temperature Tc = 26 K,new excitations emerge in the range 5-15 meV, while they are absent in the reference system LaFeAsO0.9F0.1. The strong excitations at 14.5 meV and 11.1 meV broaden rapidly around 15 K and 20 K, respectively, where each energy becomes comparable to twice of the superconducting gap. The strong excitations are ascribed to a quantum rattling, or a band motion of hydrogen, which arises only if the number of potential minima is larger than two.