Stabilization of high-temperature superconducting A15 phase La$_4$H$_{23}$ below 100 GPa

High pressure plays a crucial role in the field of superconductivity. Compressed hydride superconductors are leaders in the race for a material that can conduct electricity without resistance at high or even room temperature. Different synthetic paths under pressure will drive the formation of different polyhydrides. In the present work, through precise control of the synthesis pathway, we have discovered new lanthanum superhydride, cubic A15-type La$_4$H$_{23}$, with lower stabilization pressure compared to the reported $\textit{fcc}$ LaH$_{10}$. Superconducting La$_4$H$_{23}$ was obtained by laser heating of LaH$_3$ with ammonia borane at about 120 GPa. Transport measurements reveal the maximum critical temperature $\textit{T}$$_{C}$(onset) = 105 K at 118 GPa, as evidenced by the sharp drop of electrical resistance and the displacement of superconducting transitions in applied magnetic fields. Extrapolated upper critical field $\textit{B}$$_{C2}$(0) of La$_4$H$_{23}$ is about 33 T at 114 GPa in agreement with theoretical estimates. Discovered lanthanum hydride is a new member of the A15 family of superconductors with $\textit{T}$$_C$ exceeding the boiling point of liquid nitrogen.

[1]  D. Semenok.  Computational design of new superconducting materials and their targeted experimental synthesis , 2023, 2307.13313.

[2]  Xiaoli Huang,et al.  Evidence for Pseudogap Phase in Cerium Superhydrides: CeH$_{10}$ and CeH$_9$ , 2023, 2307.11742.

[3]  I. Troyan,et al.  Vortex Phase Dynamics in Yttrium Superhydride YH6 at Megabar Pressures. , 2023, The journal of physical chemistry letters.

[4]  I. Kruglov,et al.  Non‐Fermi‐Liquid Behavior of Superconducting SnH4 , 2023, Advanced science.

[5]  J. Bass,et al.  Superconductivity above 70 K observed in lutetium polyhydrides , 2023, Science China Physics, Mechanics & Astronomy.

[6]  L. Dubrovinsky,et al.  High-pressure synthesis of seven lanthanum hydrides with a significant variability of hydrogen content , 2022, Nature Communications.

[7]  E. Yuzbashyan,et al.  Breakdown of the Migdal-Eliashberg theory and a theory of lattice-fermionic superfluidity , 2022, Physical Review B.

[8]  Xiaoli Huang,et al.  Advances in the Synthesis and Superconductivity of Lanthanide Polyhydrides Under High Pressure , 2022, Frontiers in Electronic Materials.

[9]  Yanming Ma,et al.  High-Temperature Superconducting Phase in Clathrate Calcium Hydride CaH_{6} up to 215 K at a Pressure of 172 GPa. , 2022, Physical review letters.

[10]  Xiaoli Huang,et al.  Enhancement of superconducting properties in the La–Ce–H system at moderate pressures , 2022, Nature communications.

[11]  T. Xiang,et al.  Quantum phase transition from superconducting to insulating-like state in a pressurized cuprate superconductor , 2022, Nature Physics.

[12]  Guochun Yang,et al.  Pressure-induced hydride superconductors above 200 K , 2021, Matter and Radiation at Extremes.

[13]  C. Pickard,et al.  High T c Superconductivity in Heavy Rare Earth Hydrides , 2021, Chinese Physics Letters.

[14]  S. Mozaffari,et al.  Superconductivity up to 243 K in the yttrium-hydrogen system under high pressure , 2021, Nature Communications.

[15]  B. Monserrat,et al.  Synthesis of Weaire-Phelan Barium Polyhydride. , 2021, The journal of physical chemistry letters.

[16]  M. Calandra,et al.  Anomalous High‐Temperature Superconductivity in YH6 , 2021, Advanced materials.

[17]  Xiaoli Huang,et al.  High-Temperature Superconducting Phases in Cerium Superhydride with a T_{c} up to 115 K below a Pressure of 1 Megabar. , 2021, Physical review letters.

[18]  Xiaoli Huang,et al.  Novel Strongly Correlated Europium Superhydrides. , 2020, The journal of physical chemistry letters.

[19]  A. Oganov,et al.  Superconductivity at 253 K in lanthanum–yttrium ternary hydrides , 2020, Materials Today.

[20]  Yanming Ma,et al.  High-temperature superconductivity on the verge of a structural instability in lanthanum superhydride , 2020, Nature Communications.

[21]  Jinguang Cheng,et al.  Superconductivity of Lanthanum Superhydride Investigated Using the Standard Four-Probe Configuration under High Pressures , 2020 .

[22]  M. Einaga,et al.  Superconductivity of lanthanum hydride synthesized using AlH3 as a hydrogen source , 2020, Superconductor Science and Technology.

[23]  T. Cui,et al.  Hydrogen Pentagraphenelike Structure Stabilized by Hafnium: A High-Temperature Conventional Superconductor. , 2020, Physical review letters.

[24]  Jesse S. Smith,et al.  Ultrahigh-pressure isostructural electronic transitions in hydrogen , 2019, Nature.

[25]  Jian Lv,et al.  Route to a Superconducting Phase above Room Temperature in Electron-Doped Hydride Compounds under High Pressure. , 2019, Physical review letters.

[26]  Xiaoli Huang,et al.  Superconductivity and equation of state of lanthanum at megabar pressures , 2019, 1903.02194.

[27]  D. Graf,et al.  Superconductivity at 250 K in lanthanum hydride under high pressures , 2018, Nature.

[28]  T. Cui,et al.  Superconductivity of LaH10 and LaH16 polyhydrides , 2018, Physical Review B.

[29]  R. Hemley,et al.  Evidence for Superconductivity above 260 K in Lanthanum Superhydride at Megabar Pressures. , 2018, Physical review letters.

[30]  V. Minkov,et al.  Superconductivity at 215 K in lanthanum hydride at high pressures , 2018, 1808.07039.

[31]  Adam J. Jackson,et al.  sumo: Command-line tools for plotting and analysis of periodic *ab initio* calculations , 2018, J. Open Source Softw..

[32]  Maria Baldini,et al.  Synthesis and Stability of Lanthanum Superhydrides. , 2018, Angewandte Chemie.

[33]  I. Tanaka,et al.  Band structure diagram paths based on crystallography , 2016, 1602.06402.

[34]  A. P. Drozdov,et al.  Superconductivity above 100 K in PH3 at high pressures , 2015, 1508.06224.

[35]  A. P. Drozdov,et al.  Conventional superconductivity at 203 kelvin at high pressures in the sulfur hydride system , 2015, Nature.

[36]  I. Tanaka,et al.  First principles phonon calculations in materials science , 2015, 1506.08498.

[37]  V. Prakapenka,et al.  DIOPTAS: a program for reduction of two-dimensional X-ray diffraction data and data exploration , 2015 .

[38]  Da Li,et al.  Pressure-induced metallization of dense (H2S)2H2 with high-Tc superconductivity , 2014, Scientific Reports.

[39]  C. Scheuerlein,et al.  Effects of neutron irradiation on pinning force scaling in state-of-the-art Nb3Sn wires , 2013, 1311.6901.

[40]  Qiang Zhu,et al.  New developments in evolutionary structure prediction algorithm USPEX , 2013, Comput. Phys. Commun..

[41]  A. Oganov,et al.  How evolutionary crystal structure prediction works--and why. , 2011, Accounts of chemical research.

[42]  Stefano de Gironcoli,et al.  QUANTUM ESPRESSO: a modular and open-source software project for quantum simulations of materials , 2009, Journal of physics. Condensed matter : an Institute of Physics journal.

[43]  Y. Akahama,et al.  Pressure calibration of diamond anvil Raman gauge to 310GPa , 2006 .

[44]  A. Oganov,et al.  Crystal structure prediction using ab initio evolutionary techniques: principles and applications. , 2006, The Journal of chemical physics.

[45]  N. Ashcroft.  Hydrogen dominant metallic alloys: high temperature superconductors? , 2004, Physical review letters.

[46]  Stefano de Gironcoli,et al.  Phonons and related crystal properties from density-functional perturbation theory , 2000, cond-mat/0012092.

[47]  G. Kresse,et al.  From ultrasoft pseudopotentials to the projector augmented-wave method , 1999 .

[48]  S. Goedecker,et al.  Relativistic separable dual-space Gaussian pseudopotentials from H to Rn , 1998, cond-mat/9803286.

[49]  Burke,et al.  Generalized Gradient Approximation Made Simple. , 1996, Physical review letters.

[50]  Kresse,et al.  Efficient iterative schemes for ab initio total-energy calculations using a plane-wave basis set. , 1996, Physical review. B, Condensed matter.

[51]  Hafner,et al.  Ab initio molecular dynamics for liquid metals. , 1995, Physical review. B, Condensed matter.

[52]  Blöchl,et al.  Projector augmented-wave method. , 1994, Physical review. B, Condensed matter.

[53]  Chu,et al.  Superconductivity up to 164 K in HgBa2Cam-1CumO2m+2+ delta (m=1, 2, and 3) under quasihydrostatic pressures. , 1994, Physical review. B, Condensed matter.

[54]  Hafner,et al.  Ab initio molecular-dynamics simulation of the liquid-metal-amorphous-semiconductor transition in germanium. , 1994, Physical review. B, Condensed matter.

[55]  A. Zunger,et al.  Self-interaction correction to density-functional approximations for many-electron systems , 1981 .

[56]  R. Dynes,et al.  Transition temperature of strong-coupled superconductors reanalyzed , 1975 .

[57]  Joseph Callaway,et al.  Inhomogeneous Electron Gas , 1973 .

[58]  E. Helfand,et al.  Temperature and Purity Dependence of the Superconducting Critical Field, H c 2 . III. Electron Spin and Spin-Orbit Effects , 1966 .

[59]  W. Kohn,et al.  Self-Consistent Equations Including Exchange and Correlation Effects , 1965 .

[60]  J. Schirber,et al.  Superconductivity of β Mercury , 1959 .

[61]  A. B. Migdal,et al.  INTERACTION BETWEEN ELECTRONS AND THE LATTICE VIBRATIONS IN A NORMAL METAL , 1958 .

[62]  P. Hertel.  TRANSITION TEMPERATURE OF STRONG-COUPLED SUPERCONDUCTORS. , 1971 .