Chunjing Jia (Special Seminar)

Date(s) - Apr 26 2016
2:00 PM - 3:00 PM

SLAC Building 137, Room 322


 Understanding collective excitations and materials design in transition-metal compounds

Chunjing Jia

Postdoctoral Scholar, SIMES and SLAC

X-ray spectroscopies, including x-ray absorption, x-ray emission, resonant inelastic x-ray scattering (RIXS), and pump-probe techniques, have become significant tools in solving grand challenges in energy science, ranging from the basic understanding of complex physical phenomena to functional materials design. Theoretical simulation plays a central role in this endeavor, providing the link between spectroscopies and microscopic mechanisms, which connect directly to materials function or physical phenomena. These numerical simulations can also help to predict emergent phenomena in complex matter or to direct materials design efforts.

I will present results from large-scale numerical simulations that focus on understanding condensed matter materials and spectroscopies using different techniques. First, I will describe how to understand collective excitations in cuprates measured with RIXS. The RIXS technique has shown great potential for probing elementary excitations in strongly correlated materials; however, a theoretical understanding of the RIXS cross-section remains far from complete. I will address this issue using exact diagonalization and Monte Carlo treatments of the many-body problem [1][2][3]. Next, I will explore the design of one-dimensional transition-metal chalcogenide nanowires using diamondoids as structure-directing agents. Ab initio density functional theory has been employed for studying both the inorganic bonding configurations and underlying electronic structures. Finally, I will discuss on-going efforts to combine ab initio and charge transfer multiplet calculations for understanding materials spectroscopies within a single simulation framework, enabling us to treat reliably systems ranging from more weakly correlated metals to strongly correlated transition-metal and rare earth complexes.

[1] Jia et al, Nat Comm 5, 3314 (2014)
[2] Jia et al, NJP 14, 113038 (2012)
[3] Huang, Jia et al, Sci Rep 6, 19657 (2016)