Here we report the evidence of a disorder-to-order photo-induced phase transition (PIPT) under X-ray (hv=12.4keV) illumination in oxygen doped La 2CuO4+8. The commensurate striped polaron crystalline phase is induced by the irradiation of X-rays in a cuprate perovskite at hole doping δ ∼ 1/8 and high Cu-O micro-strain, ε > 7%. The nucleation of long range crystalline phases of holes on the oxygen 2p x,y orbitals in the CuO2 plane associated with pseudo Jahn Teller local lattice distortions (LLD) is favored by mobile counter-ions (interstitial oxygen ions in the La2O2 layer) in the temperature range 200-350 K. The PIPT appears beyond a threshold dose of 10 17 photons/cm at 220K and a power law of the polaron crystal growth is observed as a function of the X-ray illumination dose.
Photo-induced phase transition to a striped polaron crystal in cuprates / G., Campi; D., Di Castro; Bianconi, Antonio; S., Agrestini; Saini, Naurang Lal; H., Oyanagi; Antonio, Bianconi. - In: PHASE TRANSITIONS. - ISSN 0141-1594. - STAMPA. - 75:7-8(2002), pp. 927-933. [10.1080/01411590290034074]
Photo-induced phase transition to a striped polaron crystal in cuprates
BIANCONI, Antonio;SAINI, Naurang Lal;
2002
Abstract
Here we report the evidence of a disorder-to-order photo-induced phase transition (PIPT) under X-ray (hv=12.4keV) illumination in oxygen doped La 2CuO4+8. The commensurate striped polaron crystalline phase is induced by the irradiation of X-rays in a cuprate perovskite at hole doping δ ∼ 1/8 and high Cu-O micro-strain, ε > 7%. The nucleation of long range crystalline phases of holes on the oxygen 2p x,y orbitals in the CuO2 plane associated with pseudo Jahn Teller local lattice distortions (LLD) is favored by mobile counter-ions (interstitial oxygen ions in the La2O2 layer) in the temperature range 200-350 K. The PIPT appears beyond a threshold dose of 10 17 photons/cm at 220K and a power law of the polaron crystal growth is observed as a function of the X-ray illumination dose.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
