Extreme topological response in a strongly correlated electron system, Silke Paschen , Vienna University of Technology

Tuning the correlation strength of electronic materials, to map out their phase diagrams, has led to the identification and classification of novel quantum phases, thereby 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 introduce a new state of matter, the Weyl-Kondo semimetal, discovered in a joint experimental [2,3] and theoretical [4,5] effort. I will present experiments 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 to realize this new state. Indeed, our thermodynamic [2] and electrical transport [3] measurements evidence a highly unusual ``extreme topological response’’, which can be rationalized within the Weyl-Kondo semimetal picture [2-5]. I will furthermore show how this new state of matter transforms under the action of magnetic field [6], and close by highlighting the potential of such tuning studies for future discovery [7].