title: Hall effect in quantum critical charge-cluster glass.
abstract: Upon doping, cuprates undergo a quantum phase transition from an insulator to a d-wave superconductor. The nature of this transition and of the insulating state is vividly debated. Here, we study the Hall effect in La2-xSrxCuO4(LSCO) samples doped near the quantum critical point atx∼ 0.06. Dramatic fluctuations in the Hall resistance appear belowTCG∼ 1.5 K and increase as the sample is cooled down further, signaling quantum critical behavior. We explore the doping dependence of this effect in detail, by studying a combinatorial LSCO library in which the Sr content is varied in extremely fine steps,Δx∼ 0.00008. We observe that quantum charge fluctuations wash out when superconductivity emerges but can be restored when the latter is suppressed by applying a magnetic field, showing that the two instabilities compete for the ground state.
authors.affiliation: Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory, Upton, NY 11973-5000;
authors.forename: Jie
authors.initials: J
authors.lastname: Wu
authors.affiliation: Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory, Upton, NY 11973-5000;
authors.forename: Anthony T
authors.initials: AT
authors.lastname: Bollinger
authors.affiliation: Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory, Upton, NY 11973-5000; Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China;
authors.forename: Yujie
authors.initials: Y
authors.lastname: Sun
authors.affiliation: Condensed Matter Physics and Materials Science Division, Brookhaven National Laboratory, Upton, NY 11973-5000; Applied Physics Department, Yale University, New Haven CT 06520 bozovic@bnl.gov.
authors.forename: Ivan
authors.initials: I
authors.lastname: Božović
keywords: Hall effect; charge glass; high-temperature superconductors; quantum fluctuations; superconductor-to-insulator transition