Investigation of topological and emergent quantum phenomena in Kondo lattices under extreme conditions

Abstract

The thesis project of the PhD candidate, Aryella Faé Rabello (hereafter called as DD3 candidate) will deal with a current hot problem in Condensed Matter Physics: to understand the low-lying energy scales that account for an entanglement of spin and electron degrees of freedom responsible for the emergence of novel quantum phenomena and topological states. In order to reach our goals, we propose to investigate two selected strongly correlated electron systems under extreme conditions, i.e., the application of high pressure (p), high magnetic field (B) and very low temperature (T). Our proposal is rather innovative and challenges the DD3 candidate to overcome several open issues to uncover emergent quantum phenomena close to a quantum phase transition. This implies the search for new physical scenarios to account for the underlying physics of quantum critical behavior and topological states (supported by our theoretical collaborators) until the setting of new "home-built" experimental methods to measure physical properties under extreme conditions. Remarkably, such new experimental methods under extreme conditions to be set in the Institute of Physics, University of São Paulo (IF USP), are still not available in commercial setups. For the challenging experiments under extreme conditions, we propose new strategies to develop experimental methods that overcome problems as available miniaturizing space, error-prone high-pressure experiment reproducibility, pressure medium inhomogeneity, sample thermalization at ultra-low temperature. Using the state-of-the-art thin films and lithography fabrication of miniaturizing circuits, pressure gauges and temperature sensors we expect to realize physical property measurements under simultaneous extreme conditions and thus going beyond the state-of-the-art on the investigation of quantum matter. On the other hand, the materials to be investigated in this thesis, the Kondo lattices Ce3Pd20Si6 and the CeRu4Sn6, are considered at the forefront of strongly correlated electron systems. Our aim is to disentangle the different spin and electron degree of freedoms by tuning the electronic correlations of these materials under simultaneous pressure and magnetic field. The physical property measurements under extreme conditions will allow to construct a T-p-B phase diagram as well as to recognize putative quantum critical points and concomitant exotic quantum states with trivial and nontrivial topology. We expect that the results of this PhD thesis not only benefit the Young Research FAPESP project InvestInTopQuantEx (Process 2018/08845-3) but also gives an enormously contribution to answer open questions in the area of quantum matter, paving an alternative route to reach new generation of functional quantum materials with promising application in thermoelectricity, superconductivity and quantum computing. In addition, we are willing that the DD3 candidate becomes an outstanding Doctor in Physics with hard skills on development of experimental methods beyond the state-of-the-art and problem solver of hot issues at the frontier of science. (AU)