Pressure studies of the quantum critical alloyCe0.93Yb0.07CoIn5

Abstract

Here we present our experimental and theoretical study of the effects of pressure on the transport properties of the heavy-fermion alloy Ce1−xYbxCoIn5 with actual concentration x ≈ 0.07. We specifically choose this value of ytterbium concentration because the magnetic-field-induced quantum critical point, which separates the antiferromagnetic and paramagnetic states at zero temperature, approaches zero, as has been established in previous studies. Our measurements show that pressure further suppresses quantum fluctuations in this alloy, just as it does in the parent compound CeCoIn5. In contrast, the square-root temperature dependent part of resistivity remains insensitive to pressure, indicating that the heavy-quasiparticles are not involved in the inelastic scattering processes leading to such a temperature dependent resistivity. We demonstrate that the growth of the coherence temperature with pressure, as well as the decrease of the residual resistivity, can be accurately described by employing the coherent potential approximation for a disordered Kondo lattice.

Relativistic many-body theory of the electric dipole moment of Xe129 and its implications for probing new physics beyond the standard model

“…[19]. Combining this result with our present RNCCSD calculations, d a = 0.49 × 10 −20 σ C T ecm and d a = 0.32 × 10 −17 S/(|e| fm 3 ) |e|cm, and assuming that the EDM is due to a single source of either the NSM or the T-PT interaction, we obtain, respectively, the following upper limits |S| < 4.7 × 10 −10 |e|fm 3 (25) and…”

“…The theoretical foundations of Xe EDM were laid in a series of seminal papers by Flambaum and co-workers [21][22][23][24]. There have been recent advances in the relativistic manybody calculations of the EDM of this atom [8,25]. The results of these calculations are necessary for extracting CP violating coupling constants from the measured values of Xe EDM [8,25].…”

“…There have been recent advances in the relativistic manybody calculations of the EDM of this atom [8,25]. The results of these calculations are necessary for extracting CP violating coupling constants from the measured values of Xe EDM [8,25]. The relativistic coupled-cluster (RCC) theory, which is widely considered as the gold standard for the electronic structure of heavy atoms [27], was first applied to 129 Xe EDM by Singh et al by taking one particle-one hole (1p1h), two particle-two hole (2p2h) and partial three particle-three hole (3p3h) excitations [28].…”

Unconventional superconductivity in heavy-fermion compounds

“…Motivated by the anomalous physical properties exhibited by Ce 1−x Yb x CoIn 5 [172,173,174], numerous studies have been performed to probe this system's superconducting and normal state properties [179,180,181,182,183]. Interestingly, near x = 0.2 (x act 0.067), an intriguing crossover is observed.…”

“…Furthermore, from careful measurement of the in-plane magnetoresistivity of Ce 1−x Yb x CoIn 5 in magnetic fields up to 14 T [180], it has been shown that the quantum critical field associated with the fieldinduced quantum critical point (H QCP = 5 T for CeCoIn 5 ) is suppressed to 0 T near x = 0.2; therefore, the quantum critical point is suppressed by Yb substitution and the non-Fermi liquid behavior that persists to much higher Yb concentrations in Ce 1−x Yb x CoIn 5 must be decoupled from its associated quantum criticality [180]. It has also been shown that quantum critical fluctuations near x = 0.2 are suppressed with increasing pressure [183]. Despite all of these dramatic transitions and crossovers near x = 0.2, there is no apparent feature in T c (x) at this concentration.…”