Hall effect in quantum critical charge-cluster glass.

Proceedings of the National Academy of Sciences of the United States of America

PubMedID: 27044081

Wu J, Bollinger AT, Sun Y, Božovic I. Hall effect in quantum critical charge-cluster glass. Proc Natl Acad Sci USA. 2016;.
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,?x~ 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.