NMR Studies of the Competition Between Ground States in Correlated Electron Systems

点击翻译按钮获取中文摘要

This project concerns the study of the physics of competing ground states in correlated electron systems. The properties of low temperature phases as well as the phase transition between different ground states are to be determined. Tuning external parameters, such as the pressure, disorder, stoichiometry and magnetic field will control the phase transitions. Specifically, phase transitions will be investigated in which antiferromagnetism competes with either superconductivity or an ordered Spin-Peierls phase. Additional attention will be given to the properties associated with the evolution from antiferromagnetism to superconductivity in the organic superconductor (TMTSF)2PF6, and the high-Tc superconductor lanthanum cuprate co-doped with Sr and Li. The Spin-Peierls/antiferromagnetic transition in the systems (TMTTF)2x, where x = PF6 or AsF6 will be examined. The primary probe is NMR spectroscopy, under varied but controlled conditions of high pressure and high magnetic fields in order to access the different phases. The Principal Investigator will conduct this research in collaboration with graduate and undergraduate students. The students will be involved in the design, planning and execution stages of the experiments. They will learn a variety of technical skills in areas of current research and are thereby trained for employment in fields of technological importance during the next few decades of the 21st Century. %%%This project is concerned with the investigation of how novel materials can coexist in different physical states and how transitions between these states compete with one another. The materials in question are those that exhibit, for example, superconductivity and other phenomena which are intensively studied for their own intrinsic scientific interest as well for their potential applications in new technological devices. Graduate and undergraduate students, as well as postdoctoral research associates participate in this work and are thereby trained in forefront areas of condensed matter physics and materials science. They are thus prepared to enter the scientific/technical workforce of the future.***