Tailoring of the two-dimensional electron gas conductivity in LaAlO3/SrTiO3 interfaces
Abstract
The two-dimensional electron gas (2DEG) formed at the interface betweentwo band insulators LaAlO3 (LAO) and SrTiO3 (STO) is one of the mostfascinating systems in the field of oxide research. Tuning of theconductivity of this interface 2DEG and to create a spatially selectiveinsulating state is one of the key challenges in oxide electronics. Wefound that low Z ion irradiation can be utilized to manipulate theconductivity at the LAO/STO interface by carrier localization arising fromthe defects created by the ion beam exposure, and eventually producing aninsulating ground state. The results of electrical transport, Ramanspectroscopy and spectroscopic ellipsometry will be discussed. This processof ion induced defect creation results in structural changes in SrTiO3 asrevealed by the appearance of symmetry forbidden first-order TO2, andTO4 vibrationalmodes in the Raman spectra of the irradiated samples. In spectroscopicellipsometry measurements, the optical conductivity features of theirradiated interface were found to be broadened due to the localizationeffects along with a decrease of spectral weight from 4.2-5.4 eV. Theseresults indicate that the interface ground state (metallic/insulating) atthe LAO/STO can be controlled by engineering the SrTiO3 with ionirradiation. The consequences of the irradiation effects and possibleorigin of the reduction in conductivity will be discussed.
12/08/2013 at 4:00 pm
Professor K. Sridhar, Tata Institute of Fundamental Research, Mumbai
Colloquium
Lecture Hall Block A, Institute of Physics
Document Date:
NRQCD — How effective a theory of charmonium is it?
NRQCD — How effective a theory of charmonium is it?
Abstract
I will present a review and status update of Non-Relativistic QCD (NRQCD)and its application to charmonium systems. In particular, I will bediscussing the production of charmonia at colliders and critically examinehow well NRQCD fares in describing the available data. To do this, I willbegin by presenting a historical account of the theoretical models thatwere developed to understand charmonium production and how these led to thedevelopment of the effective theory approach that we call NRQCD.
05/08/2013 at 4:00 pm
Dr. Sarira Sahu, Institute of Nuclear Science National Autonomous University of Mexico, Mexico City
Origin of brane cosmological constant in warped geometry models
Abstract
Space-time with warped geometry plays important role in ourunderstanding of many phenomenology and cosmological scenario inbraneworld models. The Randall-Sundrum model in this context wasoriginally formualated on flat branes.In this work I shall try to address the possible origin of non-zerocosmological constant on the visible brane from bulk as well as branedynamics which may lead to an accelerating universe.
26/07/2013 at 4:00 pm
Dr. Natasha Sharma, USA Affiliation: University of Tennessee, Knoxville, Tennessee, USA.
General Seminar
Lecture Hall Block A, Institute of Physics
Document Date:
Study of light (anti)-nuclei production in ALICE at the LHC
