# 15th International Conference on Muon Spin Rotation, Relaxation and Resonance

28 August 2022 to 2 September 2022
Science and Technology Campus, University of Parma
Europe/Rome timezone
Submission deadline for Conference Proceedings extended until 3 October

## Anomalous electrical transport in frustrated intermetallic RCuAs$_2$ : the role of spin

28 Aug 2022, 16:00
15m
Aula dei Cavalieri, University Central Palace, via Università 12

#### Aula dei Cavalieri, University Central Palace, via Università 12

Oral Strongly correlated electron systems

### Speaker

Mae Abedi (Department of Physics, Simon Fraser University)

### Description

The Kondo effect was a longstanding theoretical puzzle, describing the scattering of conduction electrons in a metal due to dilute, localised d- or f -electron magnetic impurities and resulting in a characteristic minimum in electrical resistivity with temperature. Extended to a lattice of magnetic impurities, the Kondo effect likely explains the formation of so called heavy Fermion systems and Kondo insulators in intermetallic compounds, especially those involving rare earth elements like Ce, Pr and Yb. The hybrisation of the 4f electron states with the conduction band and resultant screening of local moments, required for Fermi liquid behavior in the Kondo lattice, competes with interactions between localised moments. The diversity in the low temperature properties of heavy Fermion metals, as well as their highly tunable nature (with magnetic field, pressure, chemical substitution), make these systems invaluable in the investigation of the emergent properties of highly correlated quantum materials.

Counterintuitively, in a class of ternary intermetallic compounds of the type RCuAs$_2$ (R = rare earth) [1], the rare earths like Sm, Gd, Tb, and Dy with strictly localised 4f character, where the Kondo effect is not anticipated, also exhibit a pronounced minimum in resistivity well above their respective magnetic ordering temperatures. Even more surprisingly, no such minimum is observed for Pr, Nd, and even Yb based members of this series. Recent theoretical predictions suggest geometric magnetic frustration plays a role [2]. More generally, frustration is thought to be an important additional tuning parameter in the Kondo lattice model. A muon spin relaxation investigation of these materials is discussed, shedding light on the role of magnetic fluctuations in determining the electronic transport in heavy Fermion materials.

[1] E.V. Sampathkumaran et al, Physical Review Letters 91, 036603 (2003);
[2] Zhentao Wang et al, Physical Review Letters 117, 206601 (2016)

### Primary authors

Mae Abedi (Department of Physics, Simon Fraser University) Dr Shayan Gheidi (Department of Physics, Simon Fraser University) Nasrin Azari (Department of Physics, Simon Fraser University) Katherine Curvelo (McMaster University) Isabelle St.-Martin (University of British Columbia) Dr Gerald D. Morris (TRIUMF) Dr Shyam Sundar (Department of Physics, Simon Fraser University) Michael Yakovlev (Department of Physics, Simon Fraser University) David Evans (Simon Fraser University) Eundeok Mun (Simon Fraser University) Jeff Sonier (Simon Fraser University) Sarah Dunsiger (TRIUMF / Simon Fraser University)

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