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Center for Nonlinear Studies |
In heavy fermion compounds the interplay of localized and itinerant electrons leads to ever new surprises. At first, these materials caught our attention by the mere existence of quasiparticles with extremely heavy masses – up to several thousand times the free electron mass. The observation that external parameters such as pressure or field can tune the quasiparticle mass and even drive it towards divergences then established the relation with quantum criticality. Here, with a strange metal state that violates the Fermi liquid paradigm and unconventional superconductivity that goes beyond the BCS framework, even more exotic phenomena were detected. Most recently, by taking into account additional degrees of freedom and alternative interactions, a wealth of new directions is being explored. Highlights of our recent research include the observation of singular charge fluctuations at a magnetic quantum critical point [1], a sequential electron localization transition in a spin-orbital coupled system [2], and the discovery of a giant spontaneous Hall effect in a nonmagnetic Kondo-driven Weyl semimetal [3].
[1] L. Prochaska, X. Li, D. C. MacFarland, A. M. Andrews, M. Bonta, E. F. Bianco, S. Yazdi, W. Schrenk, H. Detz, A. Limbeck, Q. Si, E. Ringe, G. Strasser, J. Kono, and S. Paschen, Singular charge fluctuations at a magnetic quantum critical point, arXiv:1808.02296
[2] V. Martelli, A. Cai, E. M. Nica, M. Taupin, A. Prokofiev, C. -C. Liu, H. -H. Lai, R. Yu, R. Küchler, A. M. Strydom, D. Geiger, J. Haenel, J. Larrea, Q. Si, and S. Paschen, Sequential localization and strange-metal behavior of a complex electron fluid, arXiv:1709.09376.
[3] S. Dzsaber, X. Yan, M. Taupin, G. Eguchi, A. Prokofiev, T. Shiroka, P. Blaha, O. Rubel, S. E. Grefe, H.-H. Lai, Q.Si, and S. Paschen, Giant spontaneous Hall effect in a nonmagnetic Weyl-Kondo semimetal, arXiv:1811.02819.
Host: Qimiao Si