# Welcome

We develop and apply ab initio quantum mechanical calculations to study the dynamics of electrons and excited states in materials. Our research combines theory and cutting-edge computational tools based on density functional theory and related excited-state methods, which employ massively parallel computational algorithms and use the structure of the material as the only input. Using these methods, we can investigate electrons in materials with Angstrom space and femtosecond time resolutions, with applications in energy conversion, novel electronics and optoelectronics, and ultrafast spectroscopy.

## News

- We receive funding from the DOE as part of a Caltech team investigating quantum states in two-dimensional materials 9-28-18
- Our joint theory-experiment work on the Rashba effect in halide perovskites is featured in the Caltech News! 6-20-18
- The APS March Meeting comes to Los Angeles! Marco will give an invited talk on carrier dynamics and a tutorial on electron-phonon coupling. The group will give talks on several topics 3-1-18 .
- Marco receives the NSF CAREER Award 12-15-17
- Our work on ultrafast carrier dynamics in GaN and the origin of the efficiency droop in LEDs is featured in the Caltech News! 11-20-17
- Marco receives the AFOSR Young Investigator Award 10-10-17
- Marco gives an invited talk at the World Association of Theoretical and Computational Chemistry (WATOC) 2017 conference. 9-1-17
- We receive funding from Caltech's Space Solar Initiative. 8-1-17
- Our joint experiment-theory work on hot carrier super-diffusion is featured in the Caltech News! 6-15-17
- Congratulations to Vatsal for passing the candidacy exam! 6-14-17
- Two graduate students, Hsiao-Yi Chen (Physics) and Xiao Tong (Materials Science), join the group! 4-15-17
- Marco gives talks at Trinity College, Cambridge University and EPFL on our work on electron-phonon interactions and excited carrier dynamics. 4-15-17
- Our work on energy storage using defects is accepted in Scientific Reports. 4-1-17
- Our work on Super-Diffusion of Excited Carriers in Silicon, a theory-experiment collaboration with Prof. Ahmed Zewail, is accepted in Nature Communications! 3-3-17
- Luis, Jin-Jian, Vatsal, I-Te and Marco will present at the APS March Meeting. 3-2-17
- Marco gives two talks at the TMS conference in San Diego. 3-1-17
- Marco gives a Materials Research Lecture at Caltech on the Electron-Phonon Interaction. 2-15-17
- Jin-Jian's article on ab initio polar phonon scattering is published in Physical Review B as a rapid communication. 11-28-16
- The Psi-K features Marco's review article on ab initio electron and phonon dynamics. Read the summary and the review article. 11-4-16
- The NERSC supercomputing center features Marco's research on carrier dynamics and solar cells. Read the news article and interview. 10-19-16
- We receive funding through the NSF SI2 program to develop a code for electron dynamics 9-10-16
- Marco gives an invited talk at the Keck Energy Materials Research workshop at CSU Long Beach 9-10-16
- We welcome three new graduate students, Austin, Megan, and Nien-En! 8-1-16
- Marco's research on hot carriers featured on phys.org 6-13-16
- Vatsal is awarded the prestigious Resnick graduate fellowship. Congratulations! 5-17-16
- Marco's review on computational methods for solar cells published in Energy and Environmental Science

5-12-16 - Congratulations to I-Te for passing the candidacy exam! 4-26-16
- Vatsal, I-Te, Seva, and Marco give talks at the APS March Meeting in Baltimore 3-14-16
- We receive funding through the Caltech-GIST Memorandum of Understanding! 1-27-16
- The group is awarded a start-up supercomputing time allocation at XSEDE, an NSF-funded center 1-25-16
- Marco gives an invited talk at the biennial Total Energy and Force Methods international workshop in Luxembourg 1-14-16
- The group is awarded supercomputing time at NERSC, a DOE-funded center 1-12-16
- Jin Jian Zhou joins the group as a JCAP-funded postdoc 12-15-15
- Marco will give three invited talks in Europe, at Oxford, Imperial, and CFEL in Hamburg, on our recent work on ultrafast carrier dynamics in semiconductors 11-15-15
- We obtain funding from JCAP, a DOE-BES supported hub to study the basic science of artificial photosynthesis 10-1-15
- Luis Agapito joins the group as a senior postdoc 10-1-15
- Ivanov Vsevolod (Seva) joins the group 10-1-15
- Marco wins the 2015 Psi-K Volker Heine Young Investigator Award 9-8-15

## Recent Publications

- Efficient Ab Initio Calculations of Electron-Defect

Scattering and Defect-Limited Carrier Mobility.

(Submitted). arxiv 1901.03449 - On the Physical Origin of the 1/4 Exact Exchange

in Density Functional Theory.

(Submitted). arxiv 1810.02446 - Electron-Phonon Scattering in the Presence of Soft Modes and Electron Mobility in SrTiO3
Perovskite from First Principles.

Physical Review Letters**2018**121, 226603. - Ab Initio Electron-Phonon Interactions

Using Atomic Orbital Wavefunctions.

Physical Review B**2018**97, 235146. - Theory and Ab Initio Computation of the Anisotropic Light Emission
in Monolayer Transition Metal Dichalcogenides.

Nano Letters**2018**18, 3839. - Inversion Symmetry and Bulk Rashba Effect in Methylammonium Lead Iodide Perovskite Single Crystals.

Nature Communications**2018**9, 1829. - Charge Transport in Organic Molecular Semiconductors from First Principles:
The Band-Like Hole Mobility in a Naphthalene Crystal.
Physical Review B
**2018**97, 115203. - Ultrafast Hot Carrier Dynamics in GaN and its Impact on the Efficiency Droop.
Nano Letters
**2017**, 17, 5012-5019. - Super-Diffusion of Excited Carriers in Semiconductors.

Nature Communications**2017**8:15177. - Using Defects to Store Energy in Materials – a Computational Study.
Scientific Reports
**2017**7:3403. - Ab Initio Electron Mobility and Polar Phonon Scattering in GaAs.
Physical Review B (Rapid Communication)
**2016**, 94, 201201. - Ab Initio Electronic Relaxation Times and Transport in Noble Metals.
Physical Review B
**2016**, 94, 155105. - First-Principles Dynamics of Electrons and Phonons.

Eur. J. Phys. B**2016**, 89, 239. - Computer Simulations across Time and Length Scales in Photovoltaics.
Energy Env. Sci.
**2016**, 9, 2197. - Optical and Electronic Properties of Two-Dimensional Layered Materials.
Nanophotonics
**2016**, 5, 111-125. - Theory and Computation of Hot Carriers Generated by Surface Plasmon Polaritons in Noble Metals.

Nature Communications**2015**, 6, 7044. - Exciton Radiative Lifetimes in Layered Transition Metal Dichalcogenides.
Nano Letters
**2015**, 15, 2794. - Ab Initio Study of Hot Electrons in GaAs.

PNAS**2015**, 112, 5291-5296. - Ab Initio Study of Hot Carriers in the First Picosecond after Sunlight Absorption in Silicon.

Physical Review Letters**2014**, 112, 257402.