Large positive magnetoresistance of the lightly doped La2CuO4 Mott insulator

Authors: I. Raičević, Dragana Popović, C. Panagopoulos, and T. Sasagawa

Published in: Physical Review B 81, 235104, 2010.

The  in-plane  and  out-of-plane  magnetoresistance  MR  of  single  crystals  of  La2CuO4,  lightly  doped (x=0.03) with  either  Sr (La2−xSrxCuO4) or Li (La2−xLixCuO4),  have  been  measured  in  the  fields  applied parallel and perpendicular to the CuO2  planes. Both La1.97Sr0.03CuO4 and La1.97Li0.03CuO4  exhibit the emergence of a positive MR at temperatures (T) well below the spin glass transition temperature Tsg, where charge dynamics is also glassy. This positive MR grows as T → 0 and shows hysteresis and memory. In this regime, the  in-plane  resistance  Rab(T,B) is  described  by  a  scaling  function,  suggesting  that  short-range  Coulomb repulsion between two holes in the same disorder-localized state plays a key role at low T.  The results highlight similarities  between  this  magnetic  material  and  a  broad  class  of  well-studied,  nonmagnetic  disordered insulators.

DOI: 10.1103/PhysRevB.81.235104