作者: M. Bendele , F. von Rohr , Z. Guguchia , E. Pomjakushina , A. Conder
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摘要: The oxygen isotope (O 16/O 18) effect (OIE) on the pseudogap (charge-stripe ordering) temperature T* is investigated for the cuprate superconductor La 2− x Sr x CuO 4 as a function of doping x by means of x-ray absorption near edge structure studies. A strong x dependent and sign reversed OIE on T* is observed. The OIE exponent α T* systematically decreases from α T*=− 0.6 (1.3) for x= 0.15 to α T*=− 4.4 (1.1) for x= 0.06, corresponding to increasing T* and decreasing superconducting transition temperature T c. Both T*(O 16) and T*(O 18) exhibit a linear doping dependence with different slopes and critical end points [where T*(O 16) and T*(O 18) fall to zero] at x c (O 16)= 0.201 (4) and x c (O 18)= 0.182 (3), indicating a large positive OIE of x c with an exponent of α x c= 0.84 (22). The remarkably large and strongly doping dependent OIE on T* signals a substantial involvement of the lattice in the formation of the …