We use femtosecond time-resolved optical reflectivity to study the photoexcited quasiparticle(QP)dynamics in the iron-based 112 type superconducting(SC)samples Ca0.82La0.18Fe1-xNixAs2,with x=0 and 0.024.In the parent ...We use femtosecond time-resolved optical reflectivity to study the photoexcited quasiparticle(QP)dynamics in the iron-based 112 type superconducting(SC)samples Ca0.82La0.18Fe1-xNixAs2,with x=0 and 0.024.In the parent sample,a fast and a slow relaxation emerge at temperatures below the magnetic-structure(MS)transition Tms≈50 K and the SC transition Tc≈33 K,respectively.The latter obviously corresponds to an SC QP dynamics,which is further confirmed in the x=0.024 sample with Tc≈25 K.The former suggests that a partial of photoexcited QP relaxation through a pesudogap(PG)channel,which is absent in the doped x=0.024 sample without the MS transition.展开更多
A new framework of coupled thermoelasticity is constructed in this paper based on a decomposition of internal energy into free internal energy and dissipative energy.Fundamental equations(i.e.divergence and gradient e...A new framework of coupled thermoelasticity is constructed in this paper based on a decomposition of internal energy into free internal energy and dissipative energy.Fundamental equations(i.e.divergence and gradient equations,constitutive equations including evolving laws)along with proper boundary conditions are all included in this framework,from which two novel dual-complementary variational principles with explicit functionals are proposed.Unlike the conventional thermoelastic theory,the proposed variational principles for thermoelasticity are established without the approximate assumption of small temperature changes.To verify the usefulness of the proposed variational principles in simulating coupled thermoelastic problems,a coupled thermoelastic example is numerically implemented.展开更多
基金Supported by the National Natural Science Foundation of China(Grant Nos.51875009 and 51705006)the Key Project of Beijing Municipal Natural Science Foundation and Beijing Education Committee’s Science and Technology Plan(Grant Nos.KZ201710005004 and KZ201810005001)。
文摘We use femtosecond time-resolved optical reflectivity to study the photoexcited quasiparticle(QP)dynamics in the iron-based 112 type superconducting(SC)samples Ca0.82La0.18Fe1-xNixAs2,with x=0 and 0.024.In the parent sample,a fast and a slow relaxation emerge at temperatures below the magnetic-structure(MS)transition Tms≈50 K and the SC transition Tc≈33 K,respectively.The latter obviously corresponds to an SC QP dynamics,which is further confirmed in the x=0.024 sample with Tc≈25 K.The former suggests that a partial of photoexcited QP relaxation through a pesudogap(PG)channel,which is absent in the doped x=0.024 sample without the MS transition.
文摘A new framework of coupled thermoelasticity is constructed in this paper based on a decomposition of internal energy into free internal energy and dissipative energy.Fundamental equations(i.e.divergence and gradient equations,constitutive equations including evolving laws)along with proper boundary conditions are all included in this framework,from which two novel dual-complementary variational principles with explicit functionals are proposed.Unlike the conventional thermoelastic theory,the proposed variational principles for thermoelasticity are established without the approximate assumption of small temperature changes.To verify the usefulness of the proposed variational principles in simulating coupled thermoelastic problems,a coupled thermoelastic example is numerically implemented.
