We show that it is feasible to generate sub-40-attosecond pulses with near-infrared few-cycle pulses centered at 800 nm.With proper gating technique,super-broadband continuum spectrum extending from 50 eV to above 200...We show that it is feasible to generate sub-40-attosecond pulses with near-infrared few-cycle pulses centered at 800 nm.With proper gating technique,super-broadband continuum spectrum extending from 50 eV to above 200 eV can be obtained,and the intrinsic atto-chirp can be satisfactorily compensated with C filter,producing isolated attosecond pulses with duration of 33 as.According to the wavelength scaling law of high-order harmonic generation,the proposed scheme is of great significance to develop high-flux ultrashort attosecond sources.展开更多
Resistivity and magnetization have been measured at different temperatures and magnetic fields in organic superconductorsκ-(BEDT-TTF)_(2)Cu[N(CN)_(2)]Br.The lower critical field and upper critical field are determine...Resistivity and magnetization have been measured at different temperatures and magnetic fields in organic superconductorsκ-(BEDT-TTF)_(2)Cu[N(CN)_(2)]Br.The lower critical field and upper critical field are determined,which allow to depict a complete phase diagram.Through the comparison between the upper critical fields with magnetic field perpendicular and parallel to the conducting ac-planes,and the scaling of the in-plane resistivity with field along different directions,we find that the anisotropyΓis strongly dependent on temperature.It is realized thatΓis quite large(above 20)near Tc,which satisfies the 2D model,but approaches a small value in the low-temperature region.The 2D-Tinkham model can also be used to fit the data at high temperatures.This is explained as a crossover from the orbital depairing mechanism in high-temperature and low-field region to the paramagnetic depairing mechanism in the high-field and low-temperature region.The temperature dependence of lower critical field,Hc1(T),shows a concave shape in wide temperature region.It is found that neither a single d-wave nor a single s-wave gap can fit the Hc1(T),however a two-gap model containing an s-wave and a d-wave can fit the data rather well,suggesting two-band superconductivity and an unconventional pairing mechanism in this organic superconductor.展开更多
基金supported by the National Key Research and Development Program of China(Grant No.2019YFA0307703)the National Natural Science Foundation of China(Grant Nos.12234020 and 11974426)。
文摘We show that it is feasible to generate sub-40-attosecond pulses with near-infrared few-cycle pulses centered at 800 nm.With proper gating technique,super-broadband continuum spectrum extending from 50 eV to above 200 eV can be obtained,and the intrinsic atto-chirp can be satisfactorily compensated with C filter,producing isolated attosecond pulses with duration of 33 as.According to the wavelength scaling law of high-order harmonic generation,the proposed scheme is of great significance to develop high-flux ultrashort attosecond sources.
基金the National Natural Science Foundation of China(Grant Nos.11927809 and NSFC-DFG12061131001)National Key Research and Development Program of China(Grant No.2022YFA1403200)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB25000000)。
文摘Resistivity and magnetization have been measured at different temperatures and magnetic fields in organic superconductorsκ-(BEDT-TTF)_(2)Cu[N(CN)_(2)]Br.The lower critical field and upper critical field are determined,which allow to depict a complete phase diagram.Through the comparison between the upper critical fields with magnetic field perpendicular and parallel to the conducting ac-planes,and the scaling of the in-plane resistivity with field along different directions,we find that the anisotropyΓis strongly dependent on temperature.It is realized thatΓis quite large(above 20)near Tc,which satisfies the 2D model,but approaches a small value in the low-temperature region.The 2D-Tinkham model can also be used to fit the data at high temperatures.This is explained as a crossover from the orbital depairing mechanism in high-temperature and low-field region to the paramagnetic depairing mechanism in the high-field and low-temperature region.The temperature dependence of lower critical field,Hc1(T),shows a concave shape in wide temperature region.It is found that neither a single d-wave nor a single s-wave gap can fit the Hc1(T),however a two-gap model containing an s-wave and a d-wave can fit the data rather well,suggesting two-band superconductivity and an unconventional pairing mechanism in this organic superconductor.
