Office of Research, UC Riverside
Ward Beyermann
Associate Professor
Physics and Astronomy
beyerman@ucr.edu
(951) 827-3947


Low-energy Charge Dynamics in Dirac Fermion Materials

AWARD NUMBER
004819-002
FUND NUMBER
22265
STATUS
Closed
AWARD TYPE
3-Grant
AWARD EXECUTION DATE
8/6/2010
BEGIN DATE
8/15/2010
END DATE
7/31/2013
AWARD AMOUNT
$345,000

Sponsor Information

SPONSOR AWARD NUMBER
DMR-1007020
SPONSOR
NATIONAL SCIENCE FOUNDATION
SPONSOR TYPE
Federal
FUNCTION
Organized Research
PROGRAM NAME

Proposal Information

PROPOSAL NUMBER
10041919
PROPOSAL TYPE
New
ACTIVITY TYPE
Basic Research

PI Information

PI
Beyermann, Ward P
PI TITLE
Other
PI DEPTARTMENT
Physics and Astronomy
PI COLLEGE/SCHOOL
College of Nat & Agr Sciences
CO PIs

Project Information

ABSTRACT

Technical Abstract: The objective of this project is to better understand the exotic change dynamics in materials with a Dirac point close to the Fermi energy in their band structure. The classic example is graphene; however, topological insulators, which are bulk insulators, also have Dirac fermions in unique metallic chiral edge states. Despite numerous theoretical and experimental papers on this topic, several issues are still unresolved regarding the low-frequency conductivity, the importance of quasiparticle interactions and the role of impurities and defects in their electronic properties. Terahertz time-domain spectroscopy will be used to investigate the response of these materials in this previously unexplored frequency range. Along with important fundamental issues, these materials have the potential for new technological functionality from high-performance electronic devices to topological quantum computing. Understanding the charge dynamics at terahertz frequencies is a crucial component for pursuing some of these applications. Finally, this project will train two graduate students and postdoc in a quickly emerging area of nanoscience. UCR runs a Summer Bridge to Research program that supports summer research for undergraduates in STEM fields who are Hispanic and/or come from low-income families. Each summer, a student in this program will participate on this project. Non-Technical Abstract: As a result of their unique structure, Dirac fermion materials, such as graphene and topological insulators, have exotic electronic properties and display a wide range of fascinating phenomena, which is the reason they have attracted an enormous amount of interest. Fundamentally related to their properties is the response of the electrons to external electric fields. The objective of this project is to investigate this response at terahertz frequencies using time-domain spectroscopy. This type of an investigation in a previously unexplored frequency range is relevant to resolving several issues related to how the electrons interact with defects and with each other. These materials have the potential for new technological functionality from high-performance electronic devices to topological quantum computing. In addition to advancing our fundamental understanding, knowledge of the electron?s response at these frequencies is important for pursuing some of these new applications. Finally, this project will train two graduate students and postdoc in a quickly emerging area of nanoscience. UCR runs a Summer Bridge to Research program that supports summer research for undergraduates in STEM fields who are Hispanic and/or come from low-income families. Each summer, a student in this program will participate on this project.
(Abstract from NSF)