Related papers: T/B scaling without quasiparticle mass divergence:…
We report the first study of electrical resistivity, magnetization, and specific heat on YbCo$_2$. The measurements on a single-phased sample of YbCo$_2$ bring no evidence of magnetic ordering down to 0.3 K in a zero magnetic field. The…
The Kondo model predicts that both the valence at low temperatures and its temperature dependence scale with the characteristic energy T_K of the Kondo interaction. Here, we study the evolution of the 4f occupancy with temperature in a…
Here we provide the first clear evidence of Fermi-liquid breakdown in an intermediate valence system. We employ high precision magnetization measurements of the valence fluctuating superconductor beta-YbAlB4 to probe the quantum critical…
The scaling behavior over four decades of the ratio of temperature T to magnetic field B observed in the magnetization in beta-YbAlB4 is theoretically examined. By developing a theoretical framework that exhibits the quantum critical…
We present a new Kondo-lattice system, YbNi4P2, which is a clean heavy-fermion metal with a severely reduced ferromagnetic ordering temperature at T_C=0.17K, evidenced by distinct anomalies in susceptibility, specific-heat, and resistivity…
$\beta$-YbAlB$_4$ is the first Yb-based heavy fermion superconductor with $T_{\rm c} = 80$ mK. We measured low temperature magnetization of high-purity single crystals down to $T=$ 25 mK. The measurements have revealed a considerable amount…
We present the high-precision magnetization data of the valence fluctuating heavy fermion superconductor $\beta$-YbAlB$_4$ in a wide temperature range from 0.02 K to 320 K spanning four orders of magnitude. We made detailed analyses of the…
We report on single crystal growth and physical properties of the quantum critical Kondo-lattice system YbNi$_4$(P$_{1-x}$As$_{x}$)$_2$ with $0\leq x\leq 1$ which hosts a ferromagnetic quantum critical point at $x \approx 0.1$. We performed…
We study the low-temperature properties of a Kondo lattice using the large-N formalism. For a singular density of conduction states (DOS), we generalize the single-impurity result of Withoff and Fradkin: the strong-coupling fixed point…
We present here the results of electrical resistivity {\rho}, magnetization M, ac susceptibility \c{hi}ac', and specific heat CM measurements that have been carried out on single crystals of Yb3Pt4 over a wide range of fields and…
Experimental results for the susceptibility, specific heat, 4f occupation number, Hall effect and magnetoresistance for single crystals of YbAl$_{3}$ show that, in addition to the Kondo energy scale $k_{B}T_{K}$ $% \sim $ 670K, there is a…
Dilation and thermopower measurements on YbAgGe, a heavy-fermion antiferromagnet, clarify and refine the magnetic field-temperature (H-T) phase diagram and reveal a field-induced phase with T-linear resistivity. On the low-H side of this…
$\alpha$-YbAlB$_4$ is the locally isostructural polymorph of $\beta$-YbAlB$_4$, the first example of an Yb-based heavy fermion superconductor which exhibits pronounced non-Fermi-liquid behavior above $T_{\rm c}$. Interestingly, both…
The temperature ($T$)-magnetic field ($H$) phase diagram of YbRh$_2$Si$_2$ in the vicinity of its quantum critical point is investigated by low-$T$ magnetization measurements. Our analysis reveals that the energy scale $T^\star(H)$,…
Yb$_2$Si$_2$Al may be a prototype for exploring different aspects of the Shastry-Sutherland lattice, formed by planes of orthogonally coupled Yb ions. Measurements of the magnetic susceptibility find incoherently fluctuating Yb$^{3+}$…
We report measurements of in-plane electrical and thermal transport properties in the limit $T \rightarrow 0$ near the unconventional quantum critical point in the heavy-fermion metal $\beta$-YbAlB$_4$. The high Kondo temperature $T_K$…
A review of the low temperature properties of Kondo lattice systems is presented within the mean-field approximation, focusing on the different characteristic energy scales. The Kondo temperature, T_K, and the Fermi liquid coherence energy,…
We report the temperature dependence of the Yb valence in the geometrically frustrated compound $\mathrm{YbB_4}$ from 12 to 300 K using resonant X-ray emission spectroscopy at the Yb $L_{\alpha_1}$ transition. We find that the Yb valence,…
The specific heat of polycrystalline Ce0.6La0.4Pb3 has been measured in magnetic fields ranging from 0 to 14 T. After subtraction of a lattice contribution, the specific heat between 1 K and 10 K is well described by the S=1/2…
Square-lattice systems offer a direct route for realizing 2D quantum magnetism with frustration induced by competing interactions. In this work, the square-lattice materials YbBi2IO4 and YbBi2ClO4 were investigated using a combination of…