高压下二元富氢超导体的实验研究进展

郭鉴宁; 王煜龙; 朱程程; 黄晓丽; 崔田

doi:10.11858/gywlxb.20230742

高压下二元富氢超导体的实验研究进展

doi: 10.11858/gywlxb.20230742

郭鉴宁^1,,
王煜龙¹,
朱程程¹,
黄晓丽^1,*, ,,
崔田^{1, 2}

1.
吉林大学物理学院, 吉林长春　130012
2.
宁波大学物理科学与技术学院, 浙江宁波　315211

基金项目: 国家自然科学基金（11974133，52072188）；国家重点研发计划（2022YFA1405500）；长江学者和高校创新研究团队计划（IRT_15R23）；浙江省科技创新团队（2021R01004）

详细信息

作者简介:
郭鉴宁（1998－），男，博士研究生，主要从事高压下富氢化物超导材料的实验研究. E-mail：guojn22@mails.jlu.edu.cn

通讯作者:
黄晓丽（1986－），女，博士，教授，主要从事高压下富氢化物超导材料的实验研究.E-mail：huangxiaoli@jlu.edu.cn

中图分类号: O521.2
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出版历程
- 收稿日期: 2023-09-27
- 修回日期: 2024-01-17
- 录用日期: 2024-01-17
- 网络出版日期: 2024-04-11
- 刊出日期: 2024-04-09

Progress of Experimental Research on Binary Hydride Superconductors under High Pressure

1.
College of Physics, Jilin University, Changchun 130012, Jilin, China
2.
School of Physical Science and Technology, Ningbo University, Ningbo 315211, Zhejiang, China

摘要

摘要: 自从1911年著名物理学家Onnes发现超导电性以来，人们不断努力提高超导转变温度，室温超导体是人类追逐的百年梦想。在近百年的研究历程中，铜基超导体、铁基超导体及麦克米兰极限MgB₂超导体的发现不断刷新了人们对超导领域的认知，也增强了人们进一步提高超导转变温度和挖掘高温超导机制的信心。最近，理论预测并被实验验证的新型富氢化合物显示了高温乃至室温超导电性的巨大潜力，成为室温超导体的最佳候选体系之一。值得注意的是，高压下硫氢化物和镧氢化物均具有超过200 K的超导转变温度，引领了富氢化合物的研究热潮，涌现了一些重要的理论和实验成果。本文聚焦于目前富氢化合物超导体的实验研究进展，从不同氢结构单元及氢成键特征的角度总结和归纳新型富氢化合物的晶体结构性质及超导性能。主要介绍了5种在实验上成功获得的富氢化合物超导体：间隙型、离子型、共价型、笼型及分子型。通过对比分析不同类型的富氢化合物超导体，总结出一些影响超导转变温度的普适规律，并提出目前实验上亟待解决的问题和未来主攻的实验方向。
- 高压超导 /
- 富氢化合物 /
- 金刚石对顶砧 /
- 共价型氢化物 /
- 笼型氢化物 /
- 分子型氢化物
Abstract: Since the discovery of superconductivity by the famous physicist Onnes in 1911, people have constantly tried to improve the superconducting transition temperature, and the room-temperature superconductors have also been a century-old dream of human beings. In the course of nearly a hundred years of research, it has constantly updated people’s understanding of superconductivity, enhanced people’s confidence in further improving the superconducting transition temperature and exploring the mechanism of high temperature superconductivity that scientists have discovered copper based superconductors, iron based superconductors and McMillan limit superconductors (like MgB₂). Recently, new hydrogen-rich compounds predicted theoretically and verified experimentally have shown great potential for high temperature superconductivity even room temperature superconductivity, becoming one of the best candidates for room temperature superconductors. It is worth noting that some sulfur hydrides and lanthanum hydrides have superconductivity of more than 200 K under high pressure, leading a research boom of hydrogen-rich compounds and some important theoretical and experimental results have emerged. This paper focuses on the current research progress of hydrogen-rich superconductors, summarizes the crystal structure properties and superconducting properties of new hydrogen-rich compounds from the perspective of different hydrogen structural units and hydrogen bonding characteristics. Five kinds of superconductors in hydrogen-rich compounds are introduced in this paper: interstitial type, ionic type, covalent type, cage type and molecular type, and some general rules affecting the superconducting transition temperature are summarized through comparative analysis of different types of hydrogen-rich compound superconductors. In the end, the current experimental problems to be solved and the future experimental direction are put forward.
- high-pressure superconductivity /
- hydrogen-rich compound /
- diamond anvil cell /
- covalent hydride /
- clathrate hydride /
- molecular hydride

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图 1 典型超导体发表时间和超导转变温度^{[1, 2, 8, 12, 18–20]}

Figure 1. Emergence time and corresponding critical superconducting temperature of typical superconductors^{[1, 2, 8, 12, 18–20]}

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图 2 DAC结构示意图^[21]

Figure 2. Schematic diagram of DAC^[21]

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图 3 高压电学实验中4个电极的制备流程

Figure 3. Preparation process for four electrodesunder high-pressure

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图 4 迈斯纳效应

Figure 4. Meissner effect

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图 5 (a) 125 GPa下的SiH₄样品腔，(b) 125、192 GPa下SiH₄的电阻-温度曲线，(c) SiH₄的超导转变温度随压力的变化关系^[48]

Figure 5. (a) SiH₄ sample chamber at 125 GPa; (b) resistance-temperature curves of SiH₄ at 125 and 192 GPa;(c) dependence of critical temperature with pressure for SiH₄^[48]

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图 6 (a) 恒压退火过程中电阻与温度的关系，(b) 高压下硫化氢和硫化氘电阻与温度的关系，(c) H₃S的超导转变温度随压力的变化^[8]

Figure 6. (a) Dependence of resistance to temperature in constant pressure annealing process; (b) critical temperature of sulfur hydride and sulfur deuteride at high pressure; (c) dependence of superconducting temperature with pressure for H₃S^[8]

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图 7 不同压力下H₃S的磁化率信号^[9]

Figure 7. Susceptibility at several pressure for H₃S^[9]

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图 8 (a) 40 GPa下Zr-H样品的电阻-温度变化曲线（插图为激光加热后的样品腔），(b) 40 GPa下超导转变温度随外加磁场的变化，（c）～（d）分别用WHH与GL方程外推拟合上临界磁场^[69]

Figure 8. (a) R-T curve for Zr-H sample at 40 GPa (The sample chamber is presented in inset); (b) superconductingtemperature under applied magnetic fields at 40 GPa; (c)–(d) upper critical magnetic fieldswhich extrapolated by GL and WHH equations, respectively^[69]

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图 9 (a)立方相LaH₁₀的氢笼结构^[78]，(b) Somayazulu等^[73]合成的LaH₁₀的电阻随温度的变化，(c) Drozdov等^[12]合成的LaH₁₀的电阻随压力的变化，(d) Huang等^[76]外加磁场作用下LaH₁₀的转变温度

Figure 9. (a) Clathrate structure of LaH₁₀^[78]; (b) the superconducting critical temperature of LaH₁₀ reported by Somayazulu et al.^[73];(c) the dependence of T_c with pressure for LaH₁₀ synthesized by Drozdov et al.^[12]; (d) the critical temperature forLaH₁₀ under applied magnetic fields reported by Huang et al.^[76]

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图 10 Fm $\overline{3}$ m-CeH₁₀(a)和P6₃/mmc-CeH₉(b) 的结构，CeH₁₀在0～4 T外加磁场下的电阻随压力的变化(c)^[13]

Figure 10. Structures of Fm $\overline{3}$ m-CeH₁₀(a) and P6₃/mmc-CeH₉(b); the dependence of resistance under 0−4 T with pressure for CeH₁₀(c)^[13]

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图 11 (a) Ma等^[16]测得CaH₆的电阻随温度的变化，(b) Li等^[87]测得的CaH₆电阻随温度的变化

Figure 11. (a) Dependence of resistance with temperature for CaH₆ synthesized by Ma et al.^[16]; (b) R-T curve of CaH₆ reported by Li et al.^[87]

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图 12 (a) BaH₁₂的结构示意图，(b) BaH₁₂的电阻随温度的变化^[88]

Figure 12. (a) Structure of BaH₁₂; (b) R-T curve of BaH₁₂^[88]

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图 13 一些典型超导氢化物的超导转变宽度随磁场的变化

Figure 13. Dependence of superconducting width of typical hydrides with magnetic field

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表 1 不同课题组关于H₃S体系的超导电性研究^{[8–9, 54, 57–59]}

Table 1. Superconductivity of H₃S reported by several groups^{[8–9, 54, 57–59]}

Groups	Sample synthesis	T_c/K	Corresponding pressure/GPa	Structure of superconducting phases
Drozdov et al.^[8]	Loading H₂S gas at low temperature	203	155	Undetermined
Huang et al.^[9]	Loading H₂S gas at low temperature	183	149	Calculation: Im $\overline{3}$ m-H₃S
Einaga et al.^[55]	Loading H₂S gas at low temperature	200	150	XRD: Im $\overline{3}$ m-H₃S
Goncharov et al.^[57]	Laser heated pure S and hydrogen	Unmeasured	Unmeasured	XRD: Cccm-H₃S@50 GPa， R3m-H₃S@70 GPa， Im $\overline{3}$ m-H₃S@140 GPa
Capitani et al.^[58]	Loading H₂S gas at low temperature	200	150	Undetermined
Troyan et al.^[59]	Loading H₂S gas at low temperature	140	153	Undetermined

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表 2 实验合成的典型笼型氢化物超导体^{[12–17, 72–73]}

Table 2. Typical clathrate hydride superconductors synthesized in experiment^{[12–17, 72–73]}

Sample	Space group	Pressure/GPa	T_c/K	Mensurement method
LaH₁₀	Fm $\overline{3}$ m	170	250	XRD
ThH₁₀	Fm $\overline{3}$ m	170	161	XRD
YH₆	Im $\overline{3}$ m	183	220	XRD
YH₉	P6₃/mmc	201	243	XRD
CeH₉	P6₃/mmc	130	100	XRD
CeH₁₀	Fm $\overline{3}$ m	95	115	XRD
CaH₆	Im $\overline{3}$ m	172	215	XRD

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表 3 钇超氢化物合成条件及超导转变温度

Table 3. Superconducting critical temperature of yttrium superhydrides

Samples	Ref.	Space groups	Pressures/ GPa	T_c/K	Reactants	Synthetic methods
YH₆	Troyan et al.^[14]	Im $\overline{3}$ m	166	224	Y+NH₃BH₃	Laser heated to 2400 K at high pressure
	Kong et al.^[15]	Im $\overline {3}$ m	237	208.5	YH₃+H₂	Kept the sample for three weeks under high pressure
			183	220	Y+H₂	Laser heated to 1500 K at high pressure
			159	220	YH₃+H₂	Increased the sample to 201 GPa for one month and laser heated the sample to 2000 K
YH₉	Snider et al.^[72]	P6₃/mmc	182±8	262	Y+H₂	Pressured the Y metal wrapped by Pd film and hydrogen to over 130 GPa and laser heated the sample to 1800 K
	Kong et al.^[15]	P6₃/mmc	237	227	YH₃+H₂	Maintained the sample for three weeks
			237	237	YH₃+H₂	Maintained the sample for three weeks and laser heated sample to 700 K
			201	243	YH₃+H₂	Maintained the sample for one month and laser heated sample to 2000 K
YH₄	Shao et al.^[81]	I4/mmm	155	88	YH₂+NH₃BH₃	Increased the pressure to about 150 GPa and laser heated sample to 1500 K

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表 4 理论预测的近室温或超室温二元、三元富氢化合物超导体

Table 4. Theoretical prediction of binary and ternary polyhydrides with high-temperature superconductivity

Type	Samples	Space groups	Pressure/ GPa	T_c/K	Features
Binary hydride superconductors	AcH₁₀^[97]	R $\overline{3}$ m	200	204–251	Both are predicted to be phonon-mediated superconductors with an almost empty layer of d atoms
	AcH₁₆^[97]	P $\overline{6}$ m2	150	199–241
	TbH₉^[98]	C2/c	230	220	With a typical hydrogen cage structure, the coupling of electrons and hydrogen phonons in the Tb-4f layer plays a key role in superconductivity
	TbH₁₀^[98]	R $\overline{3}$ m	270	270
	TbH₁₀^[98]	Fm $\overline{3}$ m	230	270
	ZrH₁₀^[96]	P63/mmc	250	220	Lamellar alkene H₁₀ junction
	H₃S_0.925P_0.075^[99]	Fm $\overline{3}$ m	250	280	Doping calculation based on H₃S
	H₃S_0.96Si_0.04^[99]	Fm $\overline{3}$ m	250	274	Doping calculation based on H₃S
	SrH₆^[100]	R $\overline{3}$ m	150	220–235	Hydrogen atoms are clathratelike and form twisted chains
	SrH₁₀^[101]	Cmca	300	259	Hydrogen atoms are distributed in staggered two-dimensional honeycomb layers
	MgH₆^[102]	Im $\overline{3}$ m	300	420
	YH₁₀^{[10–11, 103]}	Im $\overline{3}$ m	250	305–326	Unique H₃₂ cagelike structure
	YH₁₀^{[10–11, 103]}	Im $\overline{3}$ m	400	303
	YH₁₀^{[10–11, 103]}	Im $\overline{3}$ m	300	310
Ternary hydride superconductors	Li₂MgH₁₆^[104]	Fd $\overline{3}$ m	250	473	Wang et al.^[105] pointed that the diffusion of protons between interstitial spaces may play a key role
	CaHfH₁₂^[104]	Pm $\overline{3}$ m	300	360	The metal skeleton material should be composed of a metal element with an effective optimal valency of 3, and the metal should occupy a volume of about 0.4 in the hydride
	CaZrH₁₂^[106]	Pm $\overline{3}$ m	200	290
	Mg_0.5Ca_0.5H₆^[107]	Im $\overline{3}$ m	200	288
	Y₃CaH₂₄^[108]	Fm $\overline{3}$ m	150	250
	Y₃LuH₂₄^[109]	Fm $\overline{3}$ m	120	283
	YLu₃H₂₄^[109]	Fm $\overline{3}$ m	110	288
	YLuH₁₂^[109]	Fd $\overline{3}$ m	140	275

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