DCMPMS Seminars

Surface electronic structure and antiferromagnetism of early-transition metal/metal-oxide ultra-thin films: Mn and V systems

by Mr. Asish Kumar Kundu (Ph.D. Student, Surface Physics and Material Science Division, Saha Institute of Nuclear Physics, Kolkata)

Tuesday, October 25, 2016 from to (Asia/Kolkata)
at AG80
Description
Spontaneous occurrence of long-range magnetic order in reduced dimensions (1D chains or 2D surfaces) have been under intense investigation for many decades now. Recently, it is predicted that early transition metal over-layer on noble metal substrate can show 2D AFM and novel electronic properties but little progress has been achieved for the experimental study. In our study, we have used Low-Energy Electron Diffraction (LEED) techniques as a probe of surface antiferromagnetism and Angle-Resolved Photoelectron Spectroscopy (ARPES) for determine the electronic structure. In my talk I will show you the occurrence of 2D AFM for the monolayer of Mn on Ag(001) as well as MnO(001) systems. Although, it is well known that bulk MnO is a type–II AFM with a Neel temperature of 122 K, but the surface antiferromagnetism of MnO is not known so far. We have studied surface antiferromagnetism of MnO(001) thin film where we found an enhancement of Neel temperature. But in the case of thin film one should expect lower value of Neel temperature than the bulk one due to the finite size effect. On the other hand, V2O3 is a well-known model system to study the Metal-to-Insulator (MIT) transition. Recently, it has been reported that oxygen rich reconstructed surface does not show MIT. It is also reported that the domain formation in the film plays a great impact on the dielectric, piezoelectric and optical properties of the film. We have grown domain-V2O3 structure and study the MIT by ARPES to see the effect of domain formation on the MIT. Ultimately we found MIT does not affected by the domain formation.