Capping layer influence and isotropic in-plane upper critical field of the superconductivity at the FeSe/SrTiO3 interface
Capping layer influence and isotropic in-plane upper critical field of the superconductivity at the FeSe/SrTiO3 interface
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DOI：
10.1103/physrevmaterials.5.034802
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发表时间：
2020-10
期刊：
影响因子：
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通讯作者：
Yanan Li;Ziqiao Wang;Run Xiao;Qi Li;Ke Wang;A. Richardella;Jian Wang;N. Samarth
中科院分区：
文献类型：
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作者：
Yanan Li;Ziqiao Wang;Run Xiao;Qi Li;Ke Wang;A. Richardella;Jian Wang;N. Samarth
理解在界面处的FeSe/SrTiO 3的超导电性是一个非常当代感兴趣的问题，由于显着增加的临界温度（Tc）相比，散装FeSe，以及一个非常规的配对机制和拓扑超导的可能性。我们报告的影响的覆盖层的超导电性的FeSe薄膜生长在SrTiO 3上使用分子束外延的研究。我们在真空中使用四探针电阻测量和非原位磁输运测量来检查三个覆盖层的效果，提供明显不同的电荷转移到FeSe：化合物FeTe，非金属Te，和金属Zr。我们的研究结果表明，FeTe提供了一个最佳的上限，几乎不影响原始FeSe/SrTiO 3中发现的固有Tc，而从非金属Te帽的空穴传输完全抑制超导性，并导致绝缘行为。最后，我们使用非原位磁电阻测量FeTe帽FeSe薄膜提取的角度依赖的面内上临界磁场。我们的观察揭示了一个几乎各向同性的面内上临界场，提供洞察高温超导FeSe的对称性和配对机制。
Understanding the superconductivity at the interface of FeSe/SrTiO3 is a problem of great contemporary interest due to the significant increase in critical temperature (Tc) compared to that of bulk FeSe, as well as the possibility of an unconventional pairing mechanism and topological superconductivity. We report a study of the influence of a capping layer on superconductivity in thin films of FeSe grown on SrTiO3 using molecular beam epitaxy. We used in vacuo four-probe electrical resistance measurements and ex situ magneto-transport measurements to examine the effect of three capping layers that provide distinctly different charge transfer into FeSe: compound FeTe, non-metallic Te, and metallic Zr. Our results show that FeTe provides an optimal cap that barely influences the inherent Tc found in pristine FeSe/SrTiO3, while the transfer of holes from a non-metallic Te cap completely suppresses superconductivity and leads to insulating behavior. Finally, we used ex situ magnetoresistance measurements in FeTe-capped FeSe films to extract the angular dependence of the in-plane upper critical magnetic field. Our observations reveal an almost isotropic in-plane upper critical field, providing insight into the symmetry and pairing mechanism of high temperature superconductivity in FeSe.