报告摘要：Using a unique molecular beam epitaxy system (see Figure), we synthesize atomically smooth thin films, multilayers and superlattices of cuprates and other complex oxides. [1] Such heterostructures show high-temperature superconductivity and enable novel experiments that probe the basic physics of this phenomenon. For example, we discovered that superconducting and anti-ferromagnetic phases separate on Ångstrom scale, while the pseudo-gap state apparently mixes with the superconducting state over an anomalously large length scale (“Giant Proximity Effect”). Next, we demonstrated strong coupling of in-plane charge excitations to out-of-plane lattice vibrations [3].

In this talk, I will review our recent experiments on such films and superlattices, some of which involved the most advanced Materials Science tools such as synchrotron-based Resonant X-ray scattering and COBRA surface crystallography, Angle-resolved time-of-flight ion scattering, High-resolution transmission electron microscopy, Low-energy muon spin resonance, and Ultrafast electron diffraction. The results include discoveries of interface superconductivity [4] and of giant magneto-resistance oscillations in arrays of cuprate nano-rings [5].

[1] I. Bozovic et al., Phys. Rev. Lett. 89, 107001 (2002); P. Abbamonte et al., Science 297, 581 (2002).
[2] I. Bozovic et al., Nature 422, 873 (2003); Phys. Rev. Lett. 93, 157002 (2004).
[3] N. Gedik et al., Science 316, 425 (2007); Z. Radovic et al., Phys. Rev. B 77, 092508 (2008); H. Shim et al., Phys. Rev. Lett. 101, 247004 (2008).
[4] A. Gozar et al., Nature 455, 782 (2008); S. Smadici et al., Phys. Rev. Lett. (2009) 102, 107004 (2009), V. Butko et al, Adv. Mater. 21, 1 (2009), H. Zhou et al., Proc. US Nat. Acad. Sci. 107, 8103 (2010); G. Logvenov et al., Science 326, 699 (2009).
[5] I. Sochnikov et al, Nature Nanotechnology 5, 516 (2010).