Direct Observation of Asymmetric Sr Diffusion in Sr--Doped La2CuO4
نویسندگان
چکیده
Superconductivity in copper oxides arises when a parent insulator compound is doped beyond some critical concentration [1]. In the case of La2CuO4 (LCO), high-Tc superconductivity is obtained either by substituting La 3+ with Sr 2+ or by inserting interstitial O 2[2]. Latest advance of the unique capabilities of layer-by-layer oxide molecular beam epitaxy (MBE) allows controlling the structural composition down to the single atomic layer. Recently, we have fabricated Sr--doped La2CuO4 multilayered structures in which some atomic layers of LaO have been fully substituted by SrO layers. By varying the spacing between the LCO and SrO layers high-Tc superconductivity (~ 40 K) has been obtained.
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