Dia 15 de outubro de 2020, às 11 horas.

SCES Webinar Series

Correlation-driven electronic topology: The Weyl-Kondo semimetal Ce₃Bi₄Pd₃

Prof. Silke Paschen

(Vienna University of Technology)

The ready tunability of strongly correlated electron systems by external parameters—rooted in low and competing energy scales—has enabled us to map out their phase diagrams, thereby identifying and classifying novel quantum phases, and elucidating the underlying physics [1]. The nature of such phase diagrams in the presence of nontrivial electronic topology represents a new frontier. After a general discussion of this background I will focus on the heavy fermion material Ce₃Bi₄Pd₃ [2], a semimetallic cousin of the well-known Kondo insulator Ce₃Bi₄Pt₃. The strong spin-orbit coupling of the constituting elements together with the noncentrosymmetric and nonsymmorphic structure make this material a promising candidate for a certain type of nontrivial band topology. Indeed, our electrical transport and thermodynamic measurements evidence a highly unusual state—that of a Weyl semimetal with extreme topological response [2,3]. I will discuss how it can be understood as resulting from effects of strong correlations, leading to the notion of a Weyl-Kondo semimetal [2-5]. I will furthermore show how this new state of matter transforms under magnetic field tuning [6], and close by highlighting the potential of such tuning studies for future discovery.

[1] S. Paschen and Q. Si, Quantum phases driven by strong correlations, arXiv:2009.03602.

[2] S. Dzsaber, L. Prochaska, A. Sidorenko, G. Eguchi, R. Svagera, M. Waas, A. Prokofiev, Q. Si, and S. Paschen, Kondo insulator to semimetal transformation tuned by spin-orbit coupling, Phys. Rev. Lett. 118, 246601 (2017).

[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.

[4] H.-H. Lai, S.E. Grefe, S. Paschen, and Q. Si, Weyl–Kondo semimetal in heavy-fermion systems, PNAS 115, 93 (2018).

[5] S.E. Grefe, H.-H. Lai, S. Paschen, and Q. Si, Weyl-Kondo semimetals in nonsymmorphic systems, Phys. Rev. B 101, 075138 (2020).

[6] S. Dzsaber, D.A. Zocco, A. McCollam, F. Weickert, R. McDonald, M. Taupin, X. Yan, A. Prokofiev, L.M.K. Tang, B. Vlaar, L. Stritzinger, M. Jaime, Q. Si, and S. Paschen, Quenching a Weyl-Kondo semimetal by magnetic field, arXiv:1906.01182.

O evento será transmitido pelo Zoom:https://us02web.zoom.us/j/4396875843?pwd=T0pwTFNyTk5majkxNW1mZWhneTBBdz09 / Meeting ID: 439 687 5843 - Password: 660629   e pela página do Instituto de Física no Facebook: https://www.facebook.com/FisicaUnicamp

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