相关论文: Pressure-Induced Phase Transitions in Bilayer La$_…
The discovery of high-temperature superconductivity in La$_3$Ni$_2$O$_7$ at pressures above 14 GPa has spurred extensive research efforts. Yet, fundamental aspects of the superconducting phase, including the possibility of a filamentary…
We study the structural evolution of Sr$_3$Ir$_2$O$_7$ as a function of pressure using x-ray diffraction. At a pressure of 54 GPa at room temperature, we observe a first-order structural phase transition, associated with a change from…
We study the possibility of superconductivity in a trilayer Ruddlesden-Popper nickelate La$_4$Ni$_3$O$_{10}$ under pressure both theoretically and experimentally, making comparison with the recently discovered high $T_c$ superconductor…
The newly discovered Ruddlesden-Popper bilayer La$_3$Ni$_2$O$_7$ reaches an remarkable superconducting transition temperature $T_c$ = 80 K under a pressure of above 14 GPa. Here we propose a minimal bilayer two-orbital model of the…
A polymorph of the bilayer nickelate La3Ni2O7 that displays an alternating single-layer (SL) and trilayer (TL; 1313) stacking pattern has recently been discovered. Signatures of superconductivity under pressure have been found in this…
The precise crystal structure of La3Ni2O7 in its high-pressure superconducting state has been a subject of intense debate, with proposed models including both orthorhombic and tetragonal symmetries. Using high-pressure Raman spectroscopy…
Identification of superconductivity in the Ruddlesden-Popper phases of nickelates under high pressure remains challenging. Here, we report a comprehensive study of the crystal structure, resistance, and Meissner effect in single crystals of…
Motivated by the recent observation of superconductivity with $T_c \sim 80$ K in pressurized La3Ni2O7 [Nature 621, 493 (2023)], we explore the structural and electronic properties in A3Ni2O7 bilayer nickelates (A=La-Lu, Y, Sc) as a function…
Recently, superconductivity at high temperatures has been observed in bulk La$_3$Ni$_2$O$_{7-{\delta}}$ under high pressure. However, the attainment of high-purity La$_3$Ni$_2$O$_{7-{\delta}}$ single crystals, exhibiting controlled and…
The recent experiment shows the superconducting transition temperature in the Ruddlesden-Popper bilayer La$_3$Ni$_2$O$_{7}$ decreases monotonically with increasing pressure above 14 GPa. In order to unravel the underlying mechanism for this…
Single crystals of Ruddlesden-Popper nickelates La$_4$Ni$_3$O$_{10}$ were grown by means of the floating-zone technique at oxygen pressure of 20~bar. Our results reveal the effects of the annealing process under pressure on the crystal…
Single crystals of the metallic Ruddlesden-Popper trilayer nickelates R$_4$Ni$_3$O$_{10}$ (R=La, Pr) were successfully grown using an optical-image floating zone furnace under oxygen pressure (pO$_2$) of 20 bar for La$_4$Ni$_3$O$_{10}$ and…
La$_3$Ni$_2$O$_7$, a bilayer nickelate with Ruddlesden-Popper structure, undergoes a pressure-induced structural transition from a tilted Amam phase to an untilted Fmmm (or I4/mmm) phase near 10-15 GPa, concomitant with the emergence of…
This study explores the pressure evolution of the double perovskite Ba$_2$NiTeO$_6$ by employing experimental and computational techniques. For the study of structural and vibrational properties, synchrotron X-ray diffraction (XRD) and…
We report the discovery of a novel form of Ruddlesden-Popper (RP) oxide, which stands as the first example of long-range, coherent polymorphism in this class of inorganic solids. Rather than the well-known, uniform stacking of perovskite…
The discovery of superconductivity with onset temperature of ~80 K in pressurized bilayer Ruddlesden-Popper La3Ni2O7-d has attracted much attention. Despite intense research, determination of the exact oxygen content and understanding of…
The temperature-dependent phase transitions in Ruddlesden-Popper oxides with perovskite bilayers have been under increased scrutiny in recent years due to the so-called hybrid improper ferroelectricity that some chemical compositions…
We report a high-pressure single-crystal synchrotron x-ray diffraction on a LaAlO3 single crystal. The transition from rhombohedral to cubic at 14.8 GPa is confirmed by the loss of the superstructure reflections, whose intensity shows a…
The discovery of 80 K superconductivity in pressurized bilayer Ruddlesden-Popper (RP) nickelate La$_3$Ni$_2$O$_7$ has established a new high-temperature superconductor family. The quest to understand the governing principles of RP nickelate…
The structure of dielectric perovskite BaZrO$_3$, long known to be cubic at room temperature without any structural phase transition with variation of temperature, has been recently disputed to have different ground state structures with…