Evidence for nodeless superconducting gap in NaFe1−xCoxAs from low-temperature thermal conductivity measurements
Evidence for nodeless superconducting gap in NaFe1−xCoxAs from low-temperature thermal conductivity measurements
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DOI：
10.1209/0295-5075/101/17007
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发表时间：
2012-04
期刊：
影响因子：
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通讯作者：
S. Zhou;X. Hong;X. Qiu;B. Pan;Z. Zhang;X. Li;W. N. Dong;A. Wang;X. G. Luo;X. H. Chen;S. Y. Li
中科院分区：
文献类型：
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作者：
S. Zhou;X. Hong;X. Qiu;B. Pan;Z. Zhang;X. Li;W. N. Dong;A. Wang;X. G. Luo;X. H. Chen;S. Y. Li
最佳掺杂的NaFe 0.972Co 0.028As（Tc = 20 K）和过掺杂的NaFe 0.925Co 0.075As（Tc = 11 K）单晶的热导率被测量到50 mK。两种化合物在零磁场下均无剩余线性项κ0/T。在NaFe_（1.972）Co_（0.028）As中，施加H = 3 T（H_2H_c2/12）的磁场并没有明显增加κ0/T。过掺杂NaFe 1.925Co 0.075As的κ0/T表现出与最佳掺杂BaFe 1.85Co 0.15As 2相似的场依赖性。所有这些结果都表明，从最佳掺杂到过掺杂状态，NaFe 1 −xCoxAs中存在无节点超导能隙，各向异性或不同能隙大小之间的比值较低。
The thermal conductivity of optimally doped NaFe0.972Co0.028As (Tc ∼ 20 K) and overdoped NaFe0.925Co0.075As (Tc ∼ 11 K) single crystals were measured down to 50 mK. No residual linear term κ0/T is found in zero magnetic field for both compounds. Applying a field H = 3 T (≈Hc2/12) does not noticeably increase κ0/T in NaFe1.972Co0.028As. The κ0/T of overdoped NaFe1.925Co0.075As shows a field dependence similar to the optimally doped BaFe1.85Co0.15As2. All these results suggest nodeless superconducting gaps in NaFe1−xCoxAs from the optimal doping to the overdoped regime, with low anisotropy or ratio between the magnitudes of different gaps.