We have investigated the quasiparticle dynamics and collective excitations in the quasi-one-dimensional material ZrTe_(5) using ultrafast optical pump-probe spectroscopy.Our time-domain results reveal two coherent osc...We have investigated the quasiparticle dynamics and collective excitations in the quasi-one-dimensional material ZrTe_(5) using ultrafast optical pump-probe spectroscopy.Our time-domain results reveal two coherent oscillations having extremely low energies of hω_(1)~0.33 me V(0.08 THz)and hω_(2)-1.9 me V(0.45 THz),which are softened as the temperature approaches two different critical temperatures(~54 K and~135 K).We attribute these two collective excitations to the amplitude mode of photoinduced dynamic charge density waves in ZrTe_(5) with tremendously small nesting wave vectors.Furthermore,a peculiar quasiparticle decay process associated with the hω_(2) mode with a timescale of~1-2 ps is found below the transition temperature T*(~135 K).Our findings provide pivotal information for studying the fluctuating order parameters and their associated quasiparticle dynamics in various low-dimensional topological systems and other materials.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.11974070,11734006,11925408,and 11921004)the Frontier Science Project of Dongguan(Grant No.2019622101004)+5 种基金the National Key R&D Program of China(Grant Nos.2016YFA0300600,and 2018YFA0305700)the Strategic Priority Research Program of Chinese Academy of Sciences(Grant No.XDB33000000)the K.C.Wong Education Foundation(Grant No.GJTD-2018-01)the Beijing Natural Science Foundation(Grant No.Z180008)the Beijing Municipal Science and Technology Commission(Grant No.Z191100007219013)the CAS Interdisciplinary Innovation Team。
文摘We have investigated the quasiparticle dynamics and collective excitations in the quasi-one-dimensional material ZrTe_(5) using ultrafast optical pump-probe spectroscopy.Our time-domain results reveal two coherent oscillations having extremely low energies of hω_(1)~0.33 me V(0.08 THz)and hω_(2)-1.9 me V(0.45 THz),which are softened as the temperature approaches two different critical temperatures(~54 K and~135 K).We attribute these two collective excitations to the amplitude mode of photoinduced dynamic charge density waves in ZrTe_(5) with tremendously small nesting wave vectors.Furthermore,a peculiar quasiparticle decay process associated with the hω_(2) mode with a timescale of~1-2 ps is found below the transition temperature T*(~135 K).Our findings provide pivotal information for studying the fluctuating order parameters and their associated quasiparticle dynamics in various low-dimensional topological systems and other materials.
