Tuning the Dimensionality of Strongly Correlated Materials down to 1D

Event

When:
Fri, 24 Mar 2017, 03:00 pm - 04:00 pm
Where:
Natural Science Bldg. 112 - Louisville, KY
Category:
Current Colloquia
Who:
Dr. A. Seo
Affiliation:
University of Kentucky

Description

One-dimensional (1D) systems offer a useful platform for studying low-dimensional phenomena often associated with the onset of critical quantum phase transitions. While exactly solvable models, such as Luttinger liquid theory, are thought to describe 1D systems very well, only a few naturally occurring materials with intrinsic 1D structure are available for experimental studies. In this colloquium, I will present a new approach of synthesizing 1D quantum systems by creating dimensionally-confined stripe-superlattices from in-plane oriented 2D layered oxides. We have used this method to synthesize 1D IrO2 stripes using a-axis oriented superlattices of Sr2IrO4 and insulating (La,Sr)GaO4, both are of the K2NiF4 symmetry. The dimensional confinement of our 1D superlattices has been confirmed by structural characterizations. Optical spectroscopy shows clear anisotropic characteristics and one-dimensional electronic confinement of the spin-orbit split Jeff = 1/2 band. Spin and orbital excitations observed in resonant inelastic x-ray scattering spectra suggest larger exchange interactions and more confined orbital excitations in the 1D IrO2 stripes as compared to its 2D counterpart. The observed electronic confinement and localized spin-structure are quite consistent with density functional theory calculations. This method of transforming layered materials into 1D striped structures is a viable technique for obtaining dimensional-crossover phase transitions while tuning from two- to one-dimension.


Venue

Location:
Natural Science Bldg. 112