Phase Control in Spin-Charge-Photon Coupled Systems

某些固体中的电子由于它们之间的库仑和交换作用以及电子与晶格的相互作用而具有很强的关联性。该项目的目标是了解由电子关联带来的新相的物理学，并根据这些相之间由微弱的外部刺激触发的相变开辟一个新的电子学领域；其中包括光激发。目标材料包括过渡金属氧化物、有机固体和半导体。来自各种技术的实验数据，包括输运、磁和热测量、材料开发、激光光谱学和X射线椭偏测量，一直被理论小组询问。为高质量的晶体生长和从THz到UV的超快光学光谱奠定了坚实的技术基础。项目成员之间的协同合作对于发展材料科学领域至关重要，在该领域中，人们可以在共同的基础上讨论低能输运现象和高能光学激发；这是研究强关联电子系统的一个特别相关的方面。我们的发现包括光致绝缘体-金属相变，超导电性与金属-绝缘体相变之间的联系，轨道量子(轨道)，以及超快光开关。这些结果将是我们建立下一代电子学的基础。该计划已经很好地成为了研究强关联电子系统的世界中心。为了在项目结束后加强和扩大我们的活动，2001年4月在东京大学工程学院成立了量子相电子中心。

Electrons in certain solids have strong correlations due to the Coulomb and exchange interactions among them and the electron-lattice interaction. The objective of the Project was to understand the physics of novel phases brought about by the electron correlation and to open up a field of new electronics based on the phase transitions between these phases triggered by weak external stimuli ; among them is photo-excitation. The target materials cover transition metal oxides, organic solids, and semiconductors. Experimental data derived from various techniques including transport, magnetic, and thermal measurements, materials development, laser spectroscopy, and x-ray ellipsometry have been constantly interrogated by the theory group. A strong technical base has been established for high-quality crystal growth and for ultrafast optical spectroscopy ranging from THz to UV. The synergetic collaboration among the Project members have been essential in developing a field of materials science, in which one can discuss the low energy transport phenomena and high energy optical excitation on the common footing ; a particularly relevant aspect for the study of the strongly correlated electron systems. The list of our finding includes the photoinduced insulator-metal transition, the connection between the superconductivity and the metal-insulator transition, the orbital quanta (orbiton), and ultrafast photo-switching. These results will be the basis on which we can establish the electronics for the next generation.The Project has well served as the worldwide center for the study of strongly correlated electron systems. In order to strengthen and extend our activity after the termination of the Project, Quantum-Phase Electronic Center has been established in the School of Engineering, The University of Tokyo in April, 2001.