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Jeudi 05 June 2014, 14h
Amphi Holweck, Esc C, 1ème etage
Controlling 2D superconductivity and quantum oscillations in SrTiO3-based heterostructures
Christopher Bell
School of Physics, University of Bristol, UK
E-mail : 
At low temperatures bulk SrTiO3 is on the border of ferroelectricity, and can be doped to create a low density superconductor with high electron mobility. These fascinating properties have motivated the recent interest in low dimensional SrTiO3 heterostructures. Studies of symmetrically confined 2D superconductivity and 2D quantum oscillations in delta-doped Nb:SrTiO3 [1, 2] offer a controlled way to explore this quantum material (Fig. 1). After introducing the thin film growth technique, and the optimization of bulk-like Nb:SrTiO3 thin films, I will discuss the electronic characterization of these samples. I will also introduce recent studies utilizing coupled double delta-doped layers driving towards tunable sub-band superconductivity [3].
Fig.1 : Low-temperature Hall mobility and superconducting transition temperature vs Nb:SrTiO3 thickness. Regions are : I, insulating ; 2DM, 2D metallic ; 3DM, 3D metallic ; 2DSC, 2D superconducting ; 3DSC, 3D superconducting, taken from Ref. [2]．
References :
[1] Y. Kozuka et al., Nature 462, 487 (2009).
[2] M. Kim et al., Phys. Rev. Lett. 107, 106801 (2011).
[3] H. Inoue et al., Phys. Rev. B 88, 241104(R) (2013).