Laboratoire National des Champs Magnétiques Intenses, CNRS
报告人简介：
Mladen Horvatic is the leader of the high-field NMR group at the Laboratoire National des Champs Magnétiques Intenses (LNCMI), which is a part of the Centre National de la Recherche Scientifique (CNRS) in Grenoble, France. He has made remarkable contributions to the domains of NMR, strongly correlated systems, quantum magnetism, Bose-Einstein condensates, and physics under extreme conditions. With more than 174 publications, an h-index of 43, and approximately 6000 citations, Prof. Horvatic is a highly esteemed figure in his field. His remarkable accomplishments encompass providing the microscopic validation for the commensurate magnetic superstructure within a magnetization plateau of the renowned archetypal “Shastry-Sutherland” spin system, as well as the first microscopic indication of the FFLO phase in organic superconductors, and the discovery of a disorder-induced Bose-Einstein Condensate in a quantum spin material.
报告摘要：
Mott-insulator materials, described by spin Hamiltonians that are dominated by the Heisenberg antiferromagnetic (AF) exchange interactions are valuable model system of quantum magnetism. In magnetic field, most of them present a low-temperature AF-ordered gapless phase, which can be described in terms of the Bose-Einstein condensation (BEC). At temperatures (T) above that phase, when the dominant dimensionality (D) of the exchange interactions are quasi-1D or quasi-2D, such systems will be characterized by the critical 1D or 2D spin fluctuations. The magnetic field values that delimit the BEC phase are Quantum Critical Points, characterized by the quantum critical fluctuations. All these fluctuations precisely characterize the system and, for their low-energy limit, can be directly measured by the NMR nuclear spin-lattice relaxation rate T1-1. In this seminar I will present how the T1-1(T) data reveal the dimensionality of a spin compound, how they are analyzed for the quasi-1D and quasi-2D compounds to reveal their characteristics, and what can we learn from the quantum critical data.
邀请人：周睿（8264 9071）
联系人：胡颖（8264 9361）
地点：中国科学院物理研究所怀柔园区X1楼101会议室