Commensurate-incommensurate crossover of charge stripe in La2-xSrxNiO4 (x approximately 1/3).

Research paper by K K Ishizaka, T T Arima, Y Y Murakami, R R Kajimoto, H H Yoshizawa, N N Nagaosa, Y Y Tokura

Indexed on: 01 Jun '04Published on: 01 Jun '04Published in: Physical review letters


The temperature (T) dependence of the charge-stripe order in La2-xSrxNiO4 has been investigated in the vicinity of x approximately 1/3 by synchrotron radiation x-ray diffraction measurements. With decreasing T, a prominent commensurate-incommensurate (C-IC) crossover is observed in the x<1/3 region, while for the x>1/3 region the IC order is dominant over the whole T range. Such a C-IC crossover is interpreted as the entropy-driven self-doping of the charge stripes, and its x dependence indicates the clear electron-hole asymmetry with the x=1/3 compound as the Mott insulator.