Seminário Geral 27/05/2022: 2D metallic states and superconductivity at the interface with the charge ordered BaBiO3 semiconductor

Sobre este evento

In the last decades, the scientific community has devoted a great effort to find new emerging properties at the interfaces of oxide heterostructures with the aim of diversifying the functionalities of
existing electronic devices. Oxide materials enable the possibility of controlling the different electronic degrees of freedom, the interrelation among them and/or with the crystal structure and its dynamics. This is the
clue to design new devices with novel technologies in which the interface between the constituent materials plays a fundamental role.  In this talk, I will focus on a particular compound, BaBiO3, that is an intriguing material already in its bulk form. It becomes superconducting under hole doping with a relatively high critical temperature in the vicinity of a charge-density wave ordered phase. Despite the absence of magnetic instabilities in the parent compound, the critical temperature can be as high as 32 K for the doped BaBiO3 when K replaces Ba sites. In particular, I will describe  the electronic and crystal reconstruction at the interface of a BaBiO3/BaPbO3 bilayer through first-principles calculations. This system is interesting because 2D superconductivity has been recently observed below 3.5 K through magnetotransport studies. We find that there is a partial suppression of the BaBiO3 charge order at the interface, with a concomitant emergence of 2D metallic states. We then study their coupling to the interfacial phonon modes and suggest that the electron-phonon coupling is the physical mechanism behind the observed 2D superconductivity. These finding indicate that the breaking of charge ordering at interfaces can be a new strategy to triggers fascinating 2D phenomena.

Tópico: Seminário Geral
Hora: 27 mai. 2022 10:00 da manhã São Paulo

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