M. Brian Maple
University of California, San Diego
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Primary Section: 33, Applied Physical Sciences Secondary Section: 13, Physics Membership Type:
Member
(elected 2004)
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Research Interests
As an experimentalist working in the area of condensed matter physics, I am interested in strongly correlated electron phenomena in novel d- and f-electron materials. These phenomena include superconductivity, magnetism, and effects that arise from their interplay, valence fluctuations, heavy fermion behavior, and non-Fermi liquid behavior. I am especially interested in unconventional superconductivity that occurs in cuprates, which have superconducting critical temperatures (Tc) as high as ~ 130 K, and heavy fermion f-electron compounds, in which Tc ~ 1 K. Heavy fermion f-electron compounds are based on rare earth or actinide ions with partially-filled f-electron shells (e.g., Ce, Yb, U) in which the conduction electrons have effective masses as large as several hundred times the free electron mass. It is widely believed that the unconventional superconductivity found in these two classes of materials involves pairing of electrons in states with angular momentum greater than zero (p- or d-wave superconductivity), which is mediated by spin fluctuations. Recently, superconductivity in the filled skutterudite compound PrOs4Sb12 (Tc = 1.85 K) was discovered in our laboratory at the University of California, San Diego. This is the first heavy fermion superconductor based on Pr and may be the first example of superconducting electron pairing mediated by electric quadrupole fluctuations. There is also mounting evidence that PrOs4Sb12 exhibits triplet-spin (p-wave) superconductivity. I also have a strong interest in non-Fermi liquid behavior and other exotic states, such as unconventional superconductivity, that are found in d- and f-electron materials in the vicinity of quantum critical points, values of a control parameter, such as composition, pressure, or magnetic field, where a second order phase transition is suppressed to 0 K (also referred to as quantum critical behavior).
