It has been suggested that hydrogen-rich systems at high pressure may exhibit notably high super-conducting transition temperatures. One of the more interesting theoretical predictions was that hydrogen sulfide can be...It has been suggested that hydrogen-rich systems at high pressure may exhibit notably high super-conducting transition temperatures. One of the more interesting theoretical predictions was that hydrogen sulfide can be metallized and the high-temperature superconducting state can be induced. A record critical temperature (203 K) was later confirmed for H3S in an experiment. In this paper, we investigated, within the framework of the Eliashberg formalism, the properties of compressed MgH6, which is expected to be a very good candidate for room-temperature superconductivity. This applies particularly to the pressure range from 300 to 400 GPa, where the transition temperature is close to 400 K. Moreover, the estimated thermodynamic properties and the resulting dimensionless ratios exceed the predictions of the Bardeena€“Coopera€“Schrieffer theory. This behavior is attributed to the strong electrona€“phonon coupling and retardation effects existing in hydrogen-dominated materials under high pressure.展开更多
We theoretically investigate the possibility of achieving a superconducting state in transition-metal dichalcogenide bilayers through intercalation, a process previously and widely used to achieve metal- lization and ...We theoretically investigate the possibility of achieving a superconducting state in transition-metal dichalcogenide bilayers through intercalation, a process previously and widely used to achieve metal- lization and superconducting states in novel superconductors. For the Ca-intercalated bilayers MoSs and WS2, we find that the superconducting state is characterized by an electron-phonon coupling constant larger than 1.0 and a superconducting critical temperature of 13.3 and 9.3 K, respectively. These results are superior to other predicted or experimentally observed two-dimensional conventional ＇superconductors and suggest that the investigated materials may be good candidates for nanoscale su- perconductors. More interestingly, we proved that the obtained thermodynamic properties go beyond the predictions of the mean-field Bardeen-Cooper-Schrieffer approximation and that the calculations conducted within the framework of the strong-coupling Eliashberg theory should be treated as those that yield quantitative results.展开更多
We present a systematic analysis of the energy gap in underdoped Bi2212 superconductor as a function of temperature and hole doping level. Within the framework of the theoretical model containing the electron-phonon a...We present a systematic analysis of the energy gap in underdoped Bi2212 superconductor as a function of temperature and hole doping level. Within the framework of the theoretical model containing the electron-phonon and electron-electron-phonon pairing mechanism, we reproduced the measurement results of modern ARPES experiments with very high accuracy. We showed that the energy-gap am- plitude is very weakly dependent on the temperature but clearly dependent on the level of doping. The evidence for a non-zero energy gap above the critical temperature, referred to as a pseudogap, was also obtained.展开更多
文摘It has been suggested that hydrogen-rich systems at high pressure may exhibit notably high super-conducting transition temperatures. One of the more interesting theoretical predictions was that hydrogen sulfide can be metallized and the high-temperature superconducting state can be induced. A record critical temperature (203 K) was later confirmed for H3S in an experiment. In this paper, we investigated, within the framework of the Eliashberg formalism, the properties of compressed MgH6, which is expected to be a very good candidate for room-temperature superconductivity. This applies particularly to the pressure range from 300 to 400 GPa, where the transition temperature is close to 400 K. Moreover, the estimated thermodynamic properties and the resulting dimensionless ratios exceed the predictions of the Bardeena€“Coopera€“Schrieffer theory. This behavior is attributed to the strong electrona€“phonon coupling and retardation effects existing in hydrogen-dominated materials under high pressure.
文摘We theoretically investigate the possibility of achieving a superconducting state in transition-metal dichalcogenide bilayers through intercalation, a process previously and widely used to achieve metal- lization and superconducting states in novel superconductors. For the Ca-intercalated bilayers MoSs and WS2, we find that the superconducting state is characterized by an electron-phonon coupling constant larger than 1.0 and a superconducting critical temperature of 13.3 and 9.3 K, respectively. These results are superior to other predicted or experimentally observed two-dimensional conventional ＇superconductors and suggest that the investigated materials may be good candidates for nanoscale su- perconductors. More interestingly, we proved that the obtained thermodynamic properties go beyond the predictions of the mean-field Bardeen-Cooper-Schrieffer approximation and that the calculations conducted within the framework of the strong-coupling Eliashberg theory should be treated as those that yield quantitative results.
文摘We present a systematic analysis of the energy gap in underdoped Bi2212 superconductor as a function of temperature and hole doping level. Within the framework of the theoretical model containing the electron-phonon and electron-electron-phonon pairing mechanism, we reproduced the measurement results of modern ARPES experiments with very high accuracy. We showed that the energy-gap am- plitude is very weakly dependent on the temperature but clearly dependent on the level of doping. The evidence for a non-zero energy gap above the critical temperature, referred to as a pseudogap, was also obtained.
