Grain Boundary Dynamics in Two-Dimensional Materials

Grain boundaries in atomically thin materials represent the interfaces where crystalline domains of differing orientation meet. In two-dimensional systems such as transition metal dichalcogenides and graphene derivatives, these one-dimensional interfaces exert a profound influence on mechanical strength, electronic transport, optical responses and chemical reactivity. Grain boundary dynamics encompass the formation, migration, coalescence and annihilation of these interfaces under thermal, mechanical or electrical stimuli. Twin boundaries, tilt boundaries and twist boundaries each present distinct atomic motifs that govern local strain fields, charge densities and defect distributions. The interplay between boundary motion and external stimuli underpins phenomena ranging from domain ripening and stress relaxation to boundary-mediated catalysis and modulation of band structure. Harnessing these dynamics offers routes to engineer material properties for flexible electronics, quantum devices and catalytic platforms, with precise boundary control enabling tailored functionality across scales.

Research from Nature Portfolio

Recent studies have demonstrated that artificial arrays of mirror-twin boundaries can be introduced into monolayer MoTe₂ to form a colouring-triangle lattice. This architecture yields an electronic Janus lattice with energy-dependent atomic motifs and a Te pseudo-sublattice, supporting Dirac-like dispersions alongside flat electronic bands. Complementary theoretical modelling reveals that intrinsic domain boundaries can preserve or disrupt these features, offering a tunable electron-tunnelling barrier. Seminal work on monolayer MoS₂ has elucidated how misorientation angle at grain boundaries dictates charge-carrier mobility, with low-angle interfaces presenting higher electrostatic barriers and reduced inter-domain transport compared with high-angle configurations. Furthermore, pioneering measurements on single-layer MoS₂ have uncovered a pronounced bandgap modulation spanning nearly 0.9 eV in the vicinity of grain boundaries, underscoring the potential for boundary engineering to control optoelectronic properties.

Grain Boundary Dynamics in Two-Dimensional Materials publication trend

The graph below shows the total number of articles in grain boundary dynamics in two-dimensional materials across all publications each year (not limited to Nature Index journals).

Technical terms

Grain boundary: The one-dimensional interface between crystalline domains of differing orientation in a material.

Mirror-twin boundary: A special grain boundary formed by a 60° rotation of lattice units, resulting in mirror-symmetrical domains.

Misorientation angle: The angular difference in crystallographic orientation between adjacent grains across a boundary.

Charge-density wave (CDW): A periodic modulation of electron density that couples to lattice distortion in low-dimensional metals.

Dirac-like band: An electronic dispersion relation characterised by linear energy–momentum dependence around conical crossing points.

References

1. Catalytic Activity of Defect-Engineered Transition Me tal Dichalcogenides Mapped with Atomic-Scale Precision by Electrochemical Scanning Tunneling Microscopy. ACS Energy Letters (2023).
2. Electronic Janus lattice and kagome-like bands in coloring-triangular MoTe2 monolayers. Nature Communications (2023).
3. Visualization of Confined Electrons at Grain Boundaries in a Monolayer Charge‐Density‐Wave Metal. Advanced Science (2023).
4. Non-epitaxial growth of highly oriented transition metal dichalcogenides with density-controlled twin boundaries. The Innovation (2023).
5. Misorientation-angle-dependent electrical transport across molybdenum disulfide grain boundaries. Nature Communications (2016).
6. Bandgap tunability at single-layer molybdenum disulphide grain boundaries. Nature Communications (2015).