2024/09/26 by Talantsev, Evgeny Fedorovich, Chistyakov, Vasiliy Vladimirovich · 4 citations
#FOS: Physical sciences #Physical sciences
paper · doi:10.48612/letters/2024-3-262-268
Besides ongoing studies of phase structural transitions, pairing mechanism, and physical properties of recently discovered highly compressed high-temperature superconductor La3Ni2O7-δ, here we explored a possibility for the electron-phonon pairing mechanism as an origin of the superconducting state and determined the microcrystalline strain, ε, in high-pressure Fmmm-phase, and low-pressure Amam-phase of this nickelate. To do this, we analysed temperature dependent resistance and extracted pressure dependent Debye temperature, ΘD (P), in La3Ni2O7-δ with an approximate value of ΘD(25 GPa) = 550 K. From this we established that the La3Ni2O7-δ is strong-coupled superconductor with the electron-phonon coupling constant λe-ph(P = 22.4 GPa) =1.75. This value is close to λe-ph =1.70 of ambient pressure superconductors Nb3R (R = Sn, Al). To address ongoing discussion that the lattice strain can be the origin for the emergence of high-temperature superconductivity in the La3Ni2O7-δ, we determined the microcrystalline strain, 0.011≤ ε(P), in the high-pressure Fmmm-phase, and ε(P) < 0.011 of low-pressure Amam-phase. Our analysis showed that ε(P) has three-dome shape in the pressure range of 1.6 GPa ≤ P ≤ 41.2 GPa. One of these two ε(P) deeps at P =15 GPa coincides with the pressure at which the Amam into the Fmmm phase transition occurs. Based on our analysis, we proposed probable condition to observe the zero-resistance state in La3Ni2O7-δ.