Seminarium Oddziału Badań Magnetyków

Unraveling the magnetic and electronic properties in CeGe

dr Karan Singh

Oddział Badań Magnetyków INTiBS PAN we Wrocławiu

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Streszczenie:

Strongly correlated electrons is an exciting and diverse field in condensed matter physics. In this context, Ce-based intermetallics have gained great interest due to their exotic magnetic order and local Kondo interactions. The competing magnetic and Kondo interactions are tuned by external parameters such as pressure, magnetic field, doping, etc. As a consequence, they lead to a quantum phase transition to a new ground state such as unconventional superconductivity, non-Fermi liquid, Fermi liquid etc.
In this work, we present a detailed investigation of magnetization, electrical transport, and density-functional theory in combination with single-site dynamic mean-field theory (DFT+DMFT) on CeGe, which in an orthorhombic structure (space group Pnma). Our results show that this compound exhibits the magnetic ordering around 10.7 K which is not a simple collinear antiferromagnetic. Theoretical calculations indicate a localized 4f moment and weak coupling with the conduction electrons, which is orbital dependent. Quasiparticle is arised from the J = 5/2 sub-band [1, 2]. Unlike other nearly trivalent Ce compounds, localized 4f-moments are decoupled from the Fermi surface and Kondo lattice is not developed inside the magnetically ordered phase. In addition, evidence of the quartet state has been observed, as pointed out in the cubic (CeB6) and orthorhombic (CeSi) structures [3, 4].

References
[1] Phys. Rev. B 102, 235137 (2020).
[2] Sci. Rep. 9, 5131 (2019).
[3] Phys. Rev. Lett. 122, 076401 (2019).
[4] Phys. Rev. B 36, 5472 (1987).