Experimental Evidence of t_{2g} Electron-Gas Rashba Interaction Induced by Asymmetric Orbital Hybridization.

We report the control of Rashba spin-orbit interaction by tuning asymmetric hybridization between Ti orbitals at the LaAlO_{3}/SrTiO_{3} interface. This asymmetric orbital hybridization is modulated by introducing a LaFeO_{3} layer between LaAlO_{3} and SrTiO_{3}, which alters the Ti-O lattice polarization and traps interfacial charge carriers, resulting in a large Rashba spin-orbit effect at the interface in the absence of an external bias. This observation is verified through high-resolution electron microscopy, magnetotransport and first-principles calculations. Our results open hitherto unexplored avenues of controlling Rashba interaction to design next-generation spin orbitronics.

Observation of perfect diamagnetism and interfacial effect on the electronic structures in infinite layer Nd0.8Sr0.2NiO2 superconductors.

Nickel-based complex oxides have served as a playground for decades in the quest for a copper-oxide analog of the high-temperature superconductivity. They may provide clues towards understanding the mechanism and an alternative route for high-temperature superconductors. The recent discovery of superconductivity in the infinite-layer nickelate thin films has fulfilled this pursuit. However, material synthesis remains challenging, direct demonstration of perfect diamagnetism is still missing, and understanding of the role of the interface and bulk to the superconducting properties is still lacking. Here, we show high-quality Nd0.8Sr0.2NiO2 thin films with different thicknesses and demonstrate the interface and strain effects on the electrical, magnetic and optical properties. Perfect diamagnetism is achieved, confirming the occurrence of superconductivity in the films. Unlike the thick films in which the normal-state Hall-coefficient changes signs as the temperature decreases, the Hall-coefficient of films thinner than 5.5 nm remains negative, suggesting a thickness-driven band structure modification. Moreover, X-ray absorption spectroscopy reveals the Ni-O hybridization nature in doped infinite-layer nickelates, and the hybridization is enhanced as the thickness decreases. Consistent with band structure calculations on the nickelate/SrTiO3 heterostructure, the interface and strain effect induce a dominating electron-like band in the ultrathin film, thus causing the sign-change of the Hall-coefficient.

Role of echocardiography in the assessment of adolescents and adults with congenital heart disease.

Adolescent and adults with congenital heart disease (CHD) represent a special group of individuals. They often require regular assessment of their cardiac anatomy and functional hemodynamics. Most children with repaired CHD surviving to adulthood are either corrected or fully repaired and may not require long term follow-up. However, there are is a significant number of grown up children with residual abnormality or palliated defects, in whom full correction was not possible. Some of them are likely to present with complications and need repeated evaluation. Others may require improvement or stabilisation of their hemodynamics during stressful period like pregnancy or non-cardiac surgery. These conditions include single ventricle repair, repaired tetralogy, Mustard or Sennings operation for transposition of great arteries, aortic arch abnormalities, postatrioventricular septal defect (AVSD) repair, bicuspid aortic valve, Ebstein anomaly and unoperated congenital heart disease leading to Eisenmenger syndrome. The focus of this discussion will be mainly on this subset.