Presentation on theme: "高温与高场超导材料及其应用技术研讨会 Tian Cui State Key Laboratory of Superhard Materials, College of physics, Jilin University, Changchun, 130012,"— Presentation transcript:
高温与高场超导材料及其应用技术研讨会 Tian Cui Email: email@example.com State Key Laboratory of Superhard Materials, College of physics, Jilin University, Changchun, 130012, P. R. China 2016.4.28-29, 上海 Prediction and experimental confirmation of 200 K superconductivity in H-S system
3 高温与高场超导材料及其应用技术研讨会 Metal hydrogen is an important way to achieve room temperature superconductors Pressure ？ MH High energy density (>400 kJ/mole) Room temperature superconductor (>300 K)? E. Wigner, et al. JCP(1935) N.W. Ashcroft, PRL(1968) D.A. Papacon et al. PRB(1977) B.I. Min, et al., PRB(1984) T.W. Barbee, et al. Nature(1989) …… High pressure Metallic Hydrogen
4 高温与高场超导材料及其应用技术研讨会 ？ Pressure-induced Solid H 2 Metallization (very difficult ) No experimentally conclusive proof for metallization of hydrogen up to 360 GPa Mao suggests that metalizing pressure is 538 GPa! New Phase IV has been observed (Howie, et al, PRL 108, 125501, 2012) Experimental researches on the hydrogen at high pressures ？ Eremets, et al. NAT Mater., 10,927 (2011) Zha, et al. PRL 108, 146402 (2012) Howie, et al, PRL 108, 125501 (2012)
5 高温与高场超导材料及其应用技术研讨会 Hydrogen-rich materials High Temperature Superconductors? Hydrogen-rich materials Metallization (within current capabilities of DAC)? Chemically Precompression Hydrogen-rich H H H HVIa H HH H
6 高温与高场超导材料及其应用技术研讨会 Group IV hydrides at high pressures Most interesting hydrides: SiH 4, GeH 4, SnH 4, Si 2 H 6, SiH 4 : Pbcn ， Experiment,T c =17K GeH 4 : C2/c ， Theory ， T c =64K at 220GPa SnH 4 : P6/mmm, Theory, T c =80K at 120GPa, Si 2 H 6 : Pm-3m, Theory ， T c =139K at 275GPa  Eremets, M. I Science 319, 1506-1509 (2008). Chen, X.-J. et al. PNAS 105, 20(2008)  Gao, Ma, et al. PRL 101,107002(2008)  J. S. Tse et al. PRL 98, 117004(2007), Gao, Ma, et al PNAS 107, 1317(2010)  X. Jin and T. Cui* et al., PNAS 107, 9969 (2010).
7 高温与高场超导材料及其应用技术研讨会 H 2 S and H 2 crystallize into a ‘guest-host’ structure (H 2 S) 2 H 2 at 3.5 GPa) Strobel, et. al, PRL, 107, 255503 (2011) (H 2 S) 2 H 2 compound Low pressure ， rotationally disordered ， I4/mcm 17GPa ， order hydrogen bonds ， I222 Structures under high pressures Metallization conditions Superconductivity H3SH3S
8 高温与高场超导材料及其应用技术研讨会 High pressure structures of H 3 S P1P1 Cccm R3mR3m Im-3m Cccm P1P1 111 180 37 300 (GPa) P1P1 Cccm R3mR3m Im-3m 20 TriclinicOrthorhombicHexagonalCubic Searching structures at high pressure: USPEX+VASP
9 高温与高场超导材料及其应用技术研讨会 Triclinic phase with P1 symmetry below 37 GPa Triclinic P1, four (H 2 S) 2 H 2 f. u. H 2 molecular unit Theoretical simulated XRD, EOS and Raman are agreement with experimental ones. Insulator with band gap 3.34 eV at 20 GPa Ordered H-bonded H 2 S network
10 高温与高场超导材料及其应用技术研讨会 Orthorhombic phase with Cccm symmetry(37~111GPa) Orthorhombic Cccm, eight (H 2 S) 2 H 2 f. u. H 2 molecular unit Partial hydrogen bond symmetrization Insulator 3D H 2 S networks that trap two different types of H2 units in channels
11 高温与高场超导材料及其应用技术研讨会 Hexagonal R3m and cubic Im-3m phases( >111GPa) Hexagonal R3m, three H 3 S f. u. with a pyramidal forming, H 2 units disappear Cubic Im-3m, two H 3 S f. u, six coordination with SH 6, H 2 units disappear Band structure: Metal, ELF: covalent bond S with same symmetry: bcc R3mR3m Im-3m Electron localization function R3mR3m Im-3m No H 2 molecular unit in the R3m and Im-3m phases, different from SiH 4 (H 2 ) 2, GeH 4 (H 2 ) 2, and Ar(H 2 ) 2
12 高温与高场超导材料及其应用技术研讨会 Superconductivity under high pressure R3mR3mIm-3m Pressure(GPa)110130150200250300 λ 2.082.072.572.191.701.54 ω log 981.71125.11043.81334.61566.81680.2 T c (K, μ* =0.1) 144.7165.7174.5203.5 199.6195.9 T c (K, μ* =0.13) 135.4155.0165.0190.9 184.2179.1 Allen-Dynes modified McMillan equation Im-3m, T c =191~204 K at 200 GPa, T c decrease with pressure R3m, T c = 155~166 K at 130 GPa, T c increase with pressure High T c for H 3 S is about 200 K. T c in R3m phase increases, while in Im-3m phase, T c decreases with increasing pressure Coulomb pseudopotential * (0.1–0.13)
13 高温与高场超导材料及其应用技术研讨会 Superconductivity under high pressure R3m, 130 GPa, H vibrations contribute 66.9% of total H atoms play a significant role in superconductivity Im-3m, 200 GPa, H vibrations contribute 82.6% of total D. Duan, T. Cui*, et al. Sci. Rep., 4 (2014) 6968. Eliashberg spectral function 2 F( )
14 高温与高场超导材料及其应用技术研讨会 Sep. 3, 2015 Nature, 2015, 525, 73-76 Sep. 10, 2015 arXiv:1509.03156 Comparing experimental and theoretical results T c of Im-3m is confirmed by experimental results (H-T c ) of Drozdov et al. 203K@170GPa T c of R3m is confirmed by experimental results of Einaga et al. 188K@150GPa Our in situ Meisner effect measurements under pressures, showing that the T c of H 3 S is 183K at 149GPa.
15 高温与高场超导材料及其应用技术研讨会 Bcc and hexagonal phase of H 3 S have been verified by experiment Sep. 10, 2015 arXiv:1509.03156 Abstract: We found that the superconducting (SC) phase is mostly in good agreement with theoretically predicted hexagonal and body-centred cubic (bcc) structure, 3 [Ref.3 ， the work of cui] and coexists with elemental sulfur, which claims that the formation of 3H 2 S→2H 3 S+S is occur by the compression. 3-6 [Ref.3 and 4 ， the work of cui] XRD pattern is the mixture bcc or hexagonal phase of H 3 S and β-Po phase of S H3SH3S
16 高温与高场超导材料及其应用技术研讨会 （ 1 ） Why the H 3 S data can explain the H 2 S experiment （ 2 ） Alternative way to get the H 3 S （ 3 ） Stability of H 2 S at high pressures
18 高温与高场超导材料及其应用技术研讨会 The decomposition mechanism ： hydrogen dynamics in phases IV and V IV: protons are localized V: protons are delocalized. The proton jumping and molecular rotation enable the hydrogen to leave the sulfur lattice during the decomposition Wang, Cui*, et al. J. Chem. Phys. 132, 164506(2010)
19 高温与高场超导材料及其应用技术研讨会 Superconductivity of H 2 S Li, Ma, et al. J. Chem. Phys., 2014, 140, 174712. P-1 Cmca High pressure phases sequence: Pbcm →P2/c →Pc →Pmc21 →P-1 →Cmca Metallization above 130 GPa The highest T c reach 80 K T c increase with pressure in P-1 phase T c decrease with pressure in Cmca phase H 2 S does not decompose into sulfur and hydrogen elements at high pressure.
20 高温与高场超导材料及其应用技术研讨会 Stability of H n S (n>1) compounds H 2 S is stale below 50 GPa, H 3 S is stable up to 300 GPa H 2 S decomposes into H 3 S and sulfur at 40~50 GPa H 2 S and H 3 S coexit between 20 and 50 GPa. H 4 S, H 5 S, and H 6 S are unstable 3H 2 S→2H 3 S+S 2H 2 S+H 2 →2H 3 S h f of H n S with respect to S and H 2 under pressures. Dashed lines connect data points, and solid lines denote the convex hull. h f (H n S) = [h(H n S)−h(S)−nh(H 2 )/2]/(n+1) The formation enthalpy per atom of the most stable phases at each stoichiometry: Tie-line Convex hulls Obtained H 3 S by two approaches :
21 高温与高场超导材料及其应用技术研讨会 3H 2 S→2H 3 S+S at high pressure 1. N. Bernstein, et al. Phys. Rev. B, 2015, 91, 060511. I. Errea, et al., Phys. Rev. Lett., 2015, 114, 157004. It consists with other theoretical work And others
22 高温与高场超导材料及其应用技术研讨会 3H 2 S→2H 3 S+S at high pressure Nature, 2015, 525, 73-76 Sep. 10, 2015 arXiv:1509.03156 It has been confirmed by experimental works Precipitation of S element is found XRD=H 3 S+S
23 高温与高场超导材料及其应用技术研讨会 Conclusions Two main ways to get new H 3 S crystals at high pressures 2H 2 S + H 2 = 2H 3 S 3H 2 S = 2H 3 S+S H 3 S crystal at high pressure exhibits outstanding superconductivity with T c reaching 200 K
24 高温与高场超导材料及其应用技术研讨会 My colleague: Defang Duan, Xiaoli Huang, Xin Wang, Fubo Tian, Kuo Bao, Xilian Jin, Da Li, Bingbing Liu, Guangtian Zou, …… My students: Yunxian Liu, Hongyu Yu, Yanbin Ma,…. The National Natural Science Foundation of China, Ministry of Education of China, Ministry of Science and Technology of China. This work was supported by I would like to thank Acknowledgement