High-pressure hydrides have emerged as promising superconducting materials,attracting considerable attention in recent years.In this work,by combining the stochastic self-consistent harmonic approximation with first-p...High-pressure hydrides have emerged as promising superconducting materials,attracting considerable attention in recent years.In this work,by combining the stochastic self-consistent harmonic approximation with first-principles calculations,we elucidate crucial corrections to the vibrational and superconducting properties arising from quantum and anharmonic ionic vibrations of SnH4 in P63/mmc phase at 150–240 GPa.Compared with the classical harmonic approximation,inclusion of these effects results in a pronounced softening(over 500 cm^(−1))of hydrogen-derived optical phonon modes,and increases the superconducting critical temperature(Tc)from 65 K to 79 K(μ^(*)=0.1;isotropic Migdal–Eliashberg theory),corresponding to a 22%enhancement.For μ^(*)=0.13,the predicted Tc is approximately 70 K.Analysis of the Eliashberg spectral function confirms that hydrogen vibrational modes constitute the dominant tuning mechanism.These results provide quantitative insights into quantum ionic effects in hydride superconductors.展开更多
Hydrogen-based compounds have attracted significant attention in recent years due to the discovery of conventional superconductivity with high critical temperature under high pressure,rekindling hopes for finding room...Hydrogen-based compounds have attracted significant attention in recent years due to the discovery of conventional superconductivity with high critical temperature under high pressure,rekindling hopes for finding roomtemperature superconductors.In this study,we investigated the vibrational and superconducting properties of H_(3)Sein the Im￣3m phase under pressures of 50-200GPa.Our approach combines the stochastic self-consistent harmonic approximation and first-principles calculations to account for the quantum and anharmonic effects of ions.According to the results,these effects significantly modify the crystal structure,increasing the inner pressure by approximately 8GPa compared to situations in which they are ignored.The phonon spectra suggest that when these effects are considered,the crystal stabilizes at pressures as low as approximately 61GPa,which is significantly lower than the previously predicted value of over 100GPa.Our calculations also highlight the critical role of quantum and anharmonic effects on the electron-phonon coupling properties.Neglecting these factors can result in a significant overestimation of the superconducting critical temperature(T_(c))by approximately 4K(200GPa)to 25K(125GPa).With anharmonic phonons,the T_(c) calculated from the Migdal-Eliashberg equations reaches 200K(μ⋆=0.1,λ=4.1)as the pressure decreases to 64GPa,indicating that the crystal is a rare high-Tc superconductor at moderate pressures.展开更多
To the Editor:Mutations in mitochondrial DNA(mtDNA)cause mitochondrial diseases with multisystem involvement and variable clinical phenotypes.Myoclonic epilepsy with ragged red fiber(MERRF)syndrome is characterized by...To the Editor:Mutations in mitochondrial DNA(mtDNA)cause mitochondrial diseases with multisystem involvement and variable clinical phenotypes.Myoclonic epilepsy with ragged red fiber(MERRF)syndrome is characterized by myoclonus,generalized epilepsy,cerebellar ataxia,and mitochondrial myopathy with ragged red fibers(RRFs).Other features include hearing impairment,psychiatric disorders,and dysarthria.展开更多
基金supported by the Scientific Research Program Funded by Shaanxi Provincial Education Department (Grant No.24JP126)the National Natural Science Foundation of China (Grant No.62174136)the Natural Science Basic Research Program of Shaanxi Province (Grant No.2025JC-YBMS-063)。
文摘High-pressure hydrides have emerged as promising superconducting materials,attracting considerable attention in recent years.In this work,by combining the stochastic self-consistent harmonic approximation with first-principles calculations,we elucidate crucial corrections to the vibrational and superconducting properties arising from quantum and anharmonic ionic vibrations of SnH4 in P63/mmc phase at 150–240 GPa.Compared with the classical harmonic approximation,inclusion of these effects results in a pronounced softening(over 500 cm^(−1))of hydrogen-derived optical phonon modes,and increases the superconducting critical temperature(Tc)from 65 K to 79 K(μ^(*)=0.1;isotropic Migdal–Eliashberg theory),corresponding to a 22%enhancement.For μ^(*)=0.13,the predicted Tc is approximately 70 K.Analysis of the Eliashberg spectral function confirms that hydrogen vibrational modes constitute the dominant tuning mechanism.These results provide quantitative insights into quantum ionic effects in hydride superconductors.
基金Natural Science Foundation Project(Grant No.20230101280JC)of Jilin Provincial Department of Science and Technology.
文摘Hydrogen-based compounds have attracted significant attention in recent years due to the discovery of conventional superconductivity with high critical temperature under high pressure,rekindling hopes for finding roomtemperature superconductors.In this study,we investigated the vibrational and superconducting properties of H_(3)Sein the Im￣3m phase under pressures of 50-200GPa.Our approach combines the stochastic self-consistent harmonic approximation and first-principles calculations to account for the quantum and anharmonic effects of ions.According to the results,these effects significantly modify the crystal structure,increasing the inner pressure by approximately 8GPa compared to situations in which they are ignored.The phonon spectra suggest that when these effects are considered,the crystal stabilizes at pressures as low as approximately 61GPa,which is significantly lower than the previously predicted value of over 100GPa.Our calculations also highlight the critical role of quantum and anharmonic effects on the electron-phonon coupling properties.Neglecting these factors can result in a significant overestimation of the superconducting critical temperature(T_(c))by approximately 4K(200GPa)to 25K(125GPa).With anharmonic phonons,the T_(c) calculated from the Migdal-Eliashberg equations reaches 200K(μ⋆=0.1,λ=4.1)as the pressure decreases to 64GPa,indicating that the crystal is a rare high-Tc superconductor at moderate pressures.
文摘To the Editor:Mutations in mitochondrial DNA(mtDNA)cause mitochondrial diseases with multisystem involvement and variable clinical phenotypes.Myoclonic epilepsy with ragged red fiber(MERRF)syndrome is characterized by myoclonus,generalized epilepsy,cerebellar ataxia,and mitochondrial myopathy with ragged red fibers(RRFs).Other features include hearing impairment,psychiatric disorders,and dysarthria.
