高温超导体的超快光谱学  

Ultrafast optical spectroscopy of high-temperature superconductors

作　　者：吴穹 田义超[1] 吴艳玲 赵继民[1] 

机构地区：[1]中国科学院物理研究所,北京凝聚态物理国家实验室,北京100190

出　　处：《科学通报》2017年第34期3995-4009,共15页Chinese Science Bulletin

基　　金：国家重点研发计划(2017YFA0303603,2016YFA0300300);国家自然科学基金(11574383,11274372);中国科学院交叉创新团队、中国科学院对外合作项目(GJHZ1403)资助

摘　　要：高温超导机理至今仍是物理学的未解之谜,是凝聚态物理学皇冠上的明珠.在众多以光学手段研究超导体的方法之中,超快光谱是最精湛的观测方法之一和最强有力的调控手段之一.它能够在电荷、晶格、自旋、轨道等自由度与超导体全方位地相互作用,并能探测其激发态,能够在准粒子的超快过程、晶格相干性的调控、电子-声子耦合强度的观测、界面超导体系的探测等方面实现一些其他实验方法所不能实现的研究.本文结合具体实例介绍高温超导体的超快动力学和超快光谱学的进展,展示该方法在准粒子激发态、玻色子相干态、激光诱导的超导、界面超导等研究中的特色和独到优势,并对该领域进行展望.The mechanism of high-temperature superconductivity is still an unsolved mystery in physics, and it is the ＂pearl in the crown＂ of condensed matter physics. Among the numerous optical methods investigating superconductors, ultrafast spectroscopy is one of the most exquisite methods and the most powerful control means. It can interact with superconductors in all the charge, lattice, spin and orbital degrees of freedom. It can probe the excited state of superconductors. It can uniquely realize investigations of the ultrafast processes of quasiparticles, the coherence control of lattices, electron-phonon coupling strength, and the interface superconductivity. Here we briefly review the ultrafast optical spectroscopy（especially the ultrafast dynamics） investigations of high temperature superconductors, with concrete examples. Particularly, we demonstrate the unique virtues of this experimental method in the observation and realization of quasiparticle excited states, bosonic coherent states, laser-induced superconductivity, and interface superconductivity. We give the prospect of this area at the end. The complexity, profundity and serendipity of superconductivity quite much root in its bridging between both fermions and bosons in the condensed matters—a solid universe. Ultrafast spectroscopy can probe both the electrons and bosonic collective elementary excitations, thus making it feasible for revealing the superconducting mechanism. The time-resolved measurements provide direct evidences of the superconducting Bose-Einstein condensate and clues to distinguish it from the pseudogaps, charge density waves, spin density waves, etc. Delicate ultrafast spectroscopy investigations can also yield testifying information on the gap symmetry, including whether there is a nodal line in the system. The electron-phonon coupling constant can be obtained by directly observing the quasiparticle relaxation, which usually occurs at picosecond scales and marks the rate of energy transferring among carriers and phonons—a d

关 键 词：高温超导 超快动力学 超快光谱学 激发态 相干态 

分 类 号：O511.3[一般工业技术—材料科学与工程]