L Shu

Publications (4)14.74 Total impact

• Article: Correlated electron state in Ce(1-x)Yb(x)CoIn5 stabilized by cooperative valence fluctuations.

  L Shu, R E Baumbach, M Janoschek, E Gonzales, K Huang, T A Sayles, J Paglione, J O'Brien, J J Hamlin, D A Zocco, P-C Ho, C A McElroy, M B Maple
  [show abstract] [hide abstract]
  ABSTRACT: X-ray diffraction, electrical resistivity, magnetic susceptibility, and specific heat measurements on Ce(1-x)Yb(x)CoIn5 (0≤x≤1) reveal that many of the characteristic features of the x=0 correlated electron state are stable for x≤0.775 and that phase separation occurs for x>0.775. The stability of the correlated electron state is apparently due to cooperative behavior of the Ce and Yb ions, involving their unstable valences. Low-temperature non-Fermi liquid behavior is observed and varies with x, even though there is no readily identifiable quantum critical point. The superconducting critical temperature T(c) decreases linearly with x towards 0 K as x→1, in contrast with other HF superconductors where T(c) scales with T(coh).
  Physical Review Letters 04/2011; 106(15):156403. · 7.37 Impact Factor
• Source

  Available from: Diego A. Zocco

  Article: Unconventional T-H phase diagram in the noncentrosymmetric compound Yb2Fe12P7.

  R E Baumbach, J J Hamlin, L Shu, D A Zocco, J R O'Brien, P-C Ho, M B Maple
  [show abstract] [hide abstract]
  ABSTRACT: The temperature-(T-)magnetic-field (H) phase diagram for the noncentrosymmetric compound Yb(2)Fe(12)P(7), [corrected] determined from electrical resistivity (ρ), specific heat (C), and magnetization (M) measurements on single crystal specimens, is reported. This system exhibits a crossover from a magnetically ordered non-Fermi-liquid (NFL) phase at low H to another NFL phase at higher H. The crossover occurs near the value of H where the magnetic ordering temperature (T(M)) is no longer observable in C(T,H)/T and ρ(T,H), but not where T(M) extrapolates smoothly to T=0 K at a possible quantum critical point (QCP). This indicates the occurrence of a quantum phase transition between the two NFL phases. The lack of a clear relationship between the extrapolated QCP and NFL behavior suggests an unconventional route to the NFL ground states.
  Physical Review Letters 09/2010; 105(10):106403. · 7.37 Impact Factor
• Chapter: Strongly Correlated Electron Phenomena in the Filled Skutterudites

  M. B. Maple, R. E. Baumbach, J. J. Hamlin, P. C. Ho, L. Shu, D. E. MacLaughlin, Z. Henkie, R. Wawryk, T. Cichorek, A. Pietraszko
  [show abstract] [hide abstract]
  ABSTRACT: In the field of modern condensed matter physics, a major effort has been devoted to the study of correlated electron phenomena in solids, particularly those associated with d- and f-electrons of transition metal, rare earth, or actinide ions. One class of materials that has contributed to this enterprise has been the filled skutterudites, which have provided a rich reservoir of new materials including PrOs4Sb12: the first Pr-based heavy fermion superconductor. In this class of compounds, the delicate interplay between several types of physical phenomena can be tuned by means of various “knobs”, such as pressure and chemical substitution, to reveal the underlying mechanisms of the correlated electron behavior. In this paper, we review recent experiments on filled skutterudite compounds based on Ce and Pr “filler ions”, with particular attention to the arsenides and antimonides.
  06/2009: pages 1-18;
• Source

  Available from: Diego A. Zocco

  Article: Superconductivity in LnFePO (Ln = La, Pr, and Nd) single crystals

  R. E. Baumbach, J. J. Hamlin, L Shu, D. A. Zocco, N. M. Crisosto, M. B. Maple
  [show abstract] [hide abstract]
  ABSTRACT: Single crystals of the compounds LaFePO, PrFePO, and NdFePO have been prepared by means of a flux growth technique and studied by electrical resistivity, magnetic susceptibility and specific heat measurements. We have found that PrFePO and NdFePO display superconductivity with values of the superconducting critical temperature T_c of 3.2 K and 3.1 K, respectively. The effect of annealing on the properties of LaFePO, PrFePO, and NdFePO is also reported. The LnFePO (Ln = lanthanide) compounds are isostructural with the LnFeAsO_{1-x}F_x compounds that become superconducting with T_c values as high as 55 K for Ln = Sm. A systematic comparison of the occurrence of superconductivity in the series LnFePO and LnFeAsO_{1-x}F_x points to a possible difference in the origin of the superconductivity in these two series of compounds. Comment: submitted to the New Journal of Physics
  12/2008;