Compressive strain engineering of strong and sensitive pseudomagnetic fields in buckled graphene nanobubbles

XY Yuan and SZ Zhu, PHYSICAL REVIEW B, 107, 195417 (2023).

DOI: 10.1103/PhysRevB.107.195417

The formation of pseudomagnetic fields is a well-known consequence due to lattice strain, which has considerable effects on the electronic properties of graphene. To this end, strain engineering remains an effective route to enable unconventional electronic properties. Particularly, pseudomagnetic fields due to compressive strain have demonstrated unique advantages such as remarkably high intensities at relatively low magnitude of strains (e.g., < 5%) in several experiments. For example, pseudomagnetic fields as high as 300 T have been observed in buckled graphene nanobubbles. Recently, strong pseudomagnetic fields as high as 108 T have been measured in periodically buckled monolayer graphene, responsible for its band flattening and correlated states. Nevertheless, the general features and sensitivities of compressive strain-induced pseudomagnetic fields have been rarely explored, posing challenges for realizing their full potential. In this paper, we carry out large-scale molecular dynamics simulations to explore the properties of pseudomagnetic fields in buckled graphene nanobubbles, which are the basic representative graphene structures under compressive strains. We reveal that compressive strain can induce strong and sensitive pseudomagnetic fields for a variety of nanobubble shapes and boundary relaxation conditions. We also discuss the effect of the microscopy probe tip, which is frequently used to tune the morphologies and strain patterns. These results may offer guidance for designing electronic two- dimensional structures enabled by compressive strain engineering.

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