Kondo lattice heavy fermion behavior in CeRh₂Ga₂

Abstract

The physical properties of an intermetallic compound CeRhGa have been investigated by magnetic susceptibility [Formula: see text], isothermal magnetization M(H), heat capacity [Formula: see text], electrical resistivity [Formula: see text], thermal conductivity [Formula: see text] and thermopower S(T) measurements. CeRhGa is found to crystallize with CaBeGe-type primitive tetragonal structure (space group P4/nmm). No evidence of long range magnetic order is seen down to 1.8 K. The [Formula: see text] data show paramagnetic behavior with an effective moment [Formula: see text]/Ce indicating Ce valence state of Ce ions. The [Formula: see text] data exhibit Kondo lattice behavior with a metallic ground state. The low-T [Formula: see text] data yield an enhanced Sommerfeld coefficient [Formula: see text] mJ/mol K characterizing CeRhGa as a moderate heavy fermion system. The high-T [Formula: see text] and [Formula: see text] show an anomaly near 255 K, reflecting a phase transition. The [Formula: see text] suggests phonon dominated thermal transport with considerably higher values of Lorenz number L(T) compared to the theoretical Sommerfeld value L .

Effect of annealing on the electrical resistivity of Kondo lattice CeRh2Ga2

“…Both the structures are layered, however with different stacking orders of Rh/Cr and Ga/Si layers along the c-axis. Our magnetic susceptibility χ(T), heat capacity C p (T) and electrical resistivity ρ(T) measurements on annealed polycrystalline CeRh 2 Ga 2 revealed a Kondo lattice heavy fermion behavior with a paramagnetic ground state down to 1.85 K [16]. While the overall behavior of resitivity could be described by Kondo effect and crystal electric field effects, the ρ(T) also presents an anomalous increase below 280 K and an unusual upturn below 20 K whose origins are not clear.…”

“…In a recent study we investigated the physical properties of a Ce-based 122 compound CeRh 2 Ga 2 which forms in CaBe 2 Ge 2 -type primitive tetragonal structure (space group P4/nmm, No. 129) [16]. The CaBe 2 Ge 2 -type primitive tetragonal structure (space group P4/nmm) of CeRh 2 Ga 2 is shown in figure 1.…”

Low-Temperature Thermal Conductivity of the Two-Phase Superconductor CeRh2As2

“…This may be the reason for the absence of a more pronounced maximum in κ ph (T). A weak T dependence of κ ph without pronounced maximum is typical of Ce-based heavyfermion compounds, and has been observed, e.g., in CeCu 2 Si 2 (Franz et al, 1978), CeCu 2 (Gratz et al, 1985), CeAl 2 (Bauer et al, 1986), CeCu 4 Al (Falkowski and Kowalczyk, 2011), Ce(Ni 1−x Cu x ) 2 Si 2 (Toliński et al, 2013), and CeRh 2 Ga 2 (Anand et al, 2017).…”

“…For instance, scattering of phonons from electrons and dislocations may result in κ ph ∝ T 2 [Ziman (1960)] and phonon specular reflection results in an exponent between 2 and 3 (Li et al, 2008) dependence of κ ph has also been found and ascribed to the existence of dislocation networks (Kapoor et al, 1974;Franz et al, 1978). A quasi-linear-in-T behavior was found in the above mentioned Ce-based heavy-fermion compounds CeCu 4 Al (Falkowski and Kowalczyk, 2011) and CeRh 2 Ga 2 (Anand et al, 2017).…”

Topological Semimetal driven by Strong Correlations and Crystalline Symmetry

“…We propose two new square-net materials, CeRh 2 Ga 2 and CePt 2 Si 2 . Both have the symmetry of SG 129, remain paramagnetic and otherwise electronically disordered down to the lowest temperature of somewhat below 2 K 37,38 that has been experimentally measured, and both are moderately heavy fermion systems with the electronic specific heat coefficient C/T reaching 130 and 80 mJ/mol K 2 , respectively 37,38 Studies of these materials set the stage to search for additional strongly correlated semimetals as prescribed by our approach. The introduction of the inversion-symmetry-breaking term ∆ reduces the space-group symmetry from SG129 to SG31.…”