报告人：周迪 博士

报告时间：2024年04月08日（周一） 下午 13：30

报告地点：龙赛理科楼南楼201会议室

报告人简介：

周迪博士2020年毕业于吉林大学星空在线,星空在线(中国)崔田教授课题组，主要从事氢化物的实验合成和超导性质的研究。鉴于富氢化合物的分析与理论计算密切相关，其毕业后逐渐开始理论与实验的结合工作。2022年加入北京高压科学研究中心，利用高压核磁共振手段探究超导氢化物的超导机制。目前以一作和通讯作者在Advanced Energy Materials, Advanced Materials, JACS, Science Advances及PRB等杂志上发表文章9篇。

报告摘要：

In this talk, I will introduce some high-pressure NMR results on lanthanum hydrides. The formation of La polyhydrides was studied in diamond anvil cells at pressures up to 165 GPa in a temperature range from 5 to 300 K. To detect nuclear induction signals from the hydrogen spin-system in our micros samples, we used a system of Lenz lenses sputtered on diamond anvils. After high-temperature high-pressure synthesis of lanthanum polyhydrides, we observed a sharp weakening of the ¹H NMR signal below 227 K in a magnetic field of 7 T, corresponding to the screening of radiofrequency field by LaH_10±1 in the Meissner state. At the same temperature the NMR frequency shift, width of peaks and their intensity demonstrate a pronounced leap, whereas the spin-lattice relaxation time T₁ exhibits the Hebel-Slichter peak, characteristic of the Bardeen–Cooper–Schrieffer superconductors. Finally, an exponential decrease in the relaxation rate 1/T₁ as the temperature decreases below T_C, allowed to estimate the superconducting gap in LaH₁₀ as Δ(0) = 36.8 ± 4 meV, and R_Δ = 2Δ(0)/k_BT_C = 3.76 ± 0.42 which serves as strong arguments in favor of conventional electron-phonon superconductivity in LaH₁₀.

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