Dielectric disorder in two-dimensional materials
Journal article, 2019
Understanding and controlling disorder is key to nanotechnology and materials science. Traditionally, disorder is attributed to
local fluctuations of inherent material properties such as chemical and structural composition, doping or strain. Here, we present
a fundamentally new source of disorder in nanoscale systems that is based entirely on the local changes of the Coulomb
interaction due to fluctuations of the external dielectric environment. Using two-dimensional semiconductors as prototypes,
we experimentally monitor dielectric disorder by probing the statistics and correlations of the exciton resonances, and theoretically
analyse the influence of external screening and phonon scattering. Even moderate fluctuations of the dielectric environment
are shown to induce large variations of the bandgap and exciton binding energies up to the 100 meV range, often making
it a dominant source of inhomogeneities. As a consequence, dielectric disorder has strong implications for both the optical and
transport properties of nanoscale materials and their heterostructures.
local fluctuations of inherent material properties such as chemical and structural composition, doping or strain. Here, we present
a fundamentally new source of disorder in nanoscale systems that is based entirely on the local changes of the Coulomb
interaction due to fluctuations of the external dielectric environment. Using two-dimensional semiconductors as prototypes,
we experimentally monitor dielectric disorder by probing the statistics and correlations of the exciton resonances, and theoretically
analyse the influence of external screening and phonon scattering. Even moderate fluctuations of the dielectric environment
are shown to induce large variations of the bandgap and exciton binding energies up to the 100 meV range, often making
it a dominant source of inhomogeneities. As a consequence, dielectric disorder has strong implications for both the optical and
transport properties of nanoscale materials and their heterostructures.
Author
Archana Raja
University of California at Berkeley
Lutz Waldecker
Stanford University
Jonas Zipfel
University of Regensburg
Yeongsu Cho
University of Chicago
Samuel Brem
Chalmers, Physics, Condensed Matter Theory
Jonas Ziegler
University of Regensburg
Marvin Kulig
University of Regensburg
Takashi Taniguchi
National Institute for Materials Science (NIMS)
Kenji Watanabe
National Institute for Materials Science (NIMS)
Ermin Malic
2D-Tech
Chalmers, Physics, Condensed Matter Theory
Tony Heinz
Stanford University
Timothy Berkelbach
Columbia University
Alexey Chernikov
University of Regensburg
Nature Nanotechnology
1748-3387 (ISSN)
Vol. 14 832-837Subject Categories
Condensed Matter Physics
DOI
10.1038/s41565-019-0520-0