The tutorial will focus on the fundamental science of the mechanical
behavior and the moiré superlattice of 2D materials. Currently, strain
has been adopted to modulate a wide range of physical properties of 2D
materials, where the strain engineering of 2D materials requires a
thorough understanding of their mechanical behaviors. Recently, the
moiré superlattice and the atomic reconstruction were observed under
periodic strain potential, which can lead to some emergent and
intriguing properties, such as unconventional superconductivity and
unique optoelectronic behaviors. The tutorial will cover the fundamental
understanding of the elastic and plastic behaviors of 2D materials and
interfaces in various deformation modes, including stretching, bending,
wrinkling, crumpling, fracture, and delamination, from multiscale
(atomistic to continuum) perspectives. The tutorial will also provide an
overview of the theory of emerging properties associated with 2D
material moiré superlattice and their applications into twistronics.
Mechanics of 2D Materials and Interfaces
Rui Huang, The University of Texas at Austin
Atomically
thin materials such as graphene and other 2D materials are promising
for a wide range of applications. Among many unique and attractive
properties of 2D materials, mechanical properties play important roles
in manufacturing, integration and performance for their potential
applications. Mechanics is indispensable in the study of mechanical
properties, both theoretically and experimentally. This tutorial aims to
summarize the current understanding on the mechanics of 2D materials
including linear and nonlinear elasticity, strength and toughness, as
well as mechanical interactions such as adhesion and friction at the
interfaces of 2D materials. Theoretical and computational models will be
presented along with experimental methods for predicting and measuring
the mechanical and interfacial properties of 2D materials.
Outline:
- Linear and nonlinear elasticity
- Strength and toughness
- Adhesion and friction
Electronic Properties of Moiré Superlattices
Allan H. MacDonald, The University of Texas at Austin
When
two or more van der Waals material layers are overlaid with small
differences in lattice constant are overlaid with small relative twist
angles they form two-dimensional moiré superlattices with unit cell
areas that can be thousands of times larger than the unit cell areas of
the underlying two-dimensional crystals. When the moiré superlattice
materials are semiconductors or semimetals, low-energy electronic
properties are accurately described by low-energy models that have the
periodicity of the superlattice. These moiré materials act like crystals
with artificial giant atoms. One of the most attractive properties of
moiré materials is that the number of electrons per unit cell can be
changed by more than one using electrical gates. MacDonald will survey
the electronic properties of moiré materials, focusing on systems that
have been achieved experimentally, including graphene bilayers and
multilayers and systems based on tradition metal dichalcogenide layer
building blocks.