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.
