Percolation-induced resistivity drop in lutetium dihydride with controllable electrical conductivity over six orders of magnitude  

作　　者：Ningning Wang Jun Hou Ziyi Liu Tenglong Lu Pengfei Shan Congcong Chai Shifeng Jin Liang Ma Lifen Shi Xiao Wang Youwen Long Yue Liu Hua Zhang Xiaoli Dong Sheng Meng Miao Liu Jinguang Cheng 

机构地区：[1]Beijing National Laboratory for Condensed Matter Physics and Institute of Physics,Chinese Academy of Sciences,Beijing 100190,China [2]School of Physical Sciences,University of Chinese Academy of Sciences,Beijing 100190,China [3]Key Laboratory of Materials Physics,Ministry of Education,School of Physics and Microelectronics,Zhengzhou University,Zhengzhou 450052,China [4]Institute of Quantum Materials and Physics,Henan Academy of Sciences,Zhengzhou 450046,China [5]Songshan Lake Materials Laboratory,Dongguan 523808,China [6]Center of Materials Science and Optoelectronics Engineering,University of Chinese Academy of Sciences,Beijing 100049,China

出　　处：《Science China(Physics,Mechanics & Astronomy)》2023年第9期102-108,共7页中国科学：物理学、力学、天文学（英文版）

基　　金：supported by the National Natural Science Foundation of China (Grant Nos. 12025408, 11921004, 11834016, and 11888101);the Beijing Natural Science Foundation (Grant No. Z190008);the National Key R&D Program of China (Grant Nos. 2021YFA1400200, and 2021YFA1400300);the Strategic Priority Research Program of CAS (Grant No. XDB33000000)。

摘　　要：The recent report of near-ambient superconductivity in the nitrogen-doped lutetium hydride has attracted considerable attention.Subsequent follow-up studies confirmed the pressure-induced color changes in both N-free and N-doped LuH_(2) but failed to reproduce superconductivity. It remains a puzzle why the samples in the original report exhibited pronounced resistance anomaly reminiscent of the superconducting transition. Here, we show that percolation of metallic grains with high conductivity through the insulating surfaces in cold-pressed LuH_(2) samples can occasionally produce sharp resistance drops, which even display magnetic field and/or current dependences but stay far from zero resistance. The insulating surface of LuH2grain should be attributed to the modification of hydrogen stoichiometry or the contamination by oxygen/nitrogen, resulting in an increase of resistance by over six orders of magnitude. Such an effect is more significant than that discovered recently in LaH_(3±x), which may indicate that LuH_(2) can be a potential superionic conductor. Our results call for caution in asserting the resistivity drops as superconductivity and invalidate the background subtraction in analyzing the corresponding resistance data.

关 键 词：LuH_(2) PERCOLATION resistance drop SUPERCONDUCTIVITY superionic conductor 

分 类 号：O469[理学—凝聚态物理]