Strain Engineering

Strain Engineering

Keyworks: Artificial muscles, Ideal strength, Nanomechanics, Electromechanics, 2D materials

Strain engineering involves manipulating the mechanical deformation (strain) of materials to enhance their physical properties and vice versa.

Strain controls physics:

The “forward control” utilizes strain engineering to manipulate functional properties such as electronic band structure, electrical conductivity, thermal conductivity, and ferroelectricity. Strain engineering can be precisely implemented experimentally at the nanoscale by using atomic force microscopy. As a result, strain serves as an effective tool for controlling the physical properties of materials, which can enhance the overall performance of specific devices. For example, we discovered that by applying strain, we can adjust the energy band structure of a material, thereby improving its thermoelectric properties. We also found that the strain can break the symmetry of the 2D materials, significantly enhancing the nonlinear optical response of the 2D materials. In this topic, our goal is to improve material performance, such as enhancing carrier mobility in semiconductors, tuning catalytic activity, energy conversion, or creating new functionalities by using strain.

Physics controls strain:

In contrast, the “inverse control” utilizes the physical properties to manipulate the materials deformation (i.e., actuation) and strength properties of the materials. One notable application of inverse design is in the development of artificial muscles. An artificial muscle is a novel actuator material that changes its shape when excited electrically, similar to a natural muscle. For example, carbon nanotubes are recognized as some of the strongest and stiffest materials available. They can also undergo reversible contractions and expansions in volume when an electric voltage is applied. However, the strain produced by carbon nanotubes under voltage is only about 1%, significantly less than that of natural muscles, which can achieve approximately 30% strain. To address this limitation, I have developed a theoretical and computational framework for designing new actuator materials using 2D materials and carbon-based substances. Our research paves the way for advancements in strain engineering, leading to the creation of functional materials suitable for applications not only in artificial muscles but also in nano actuators and nanobots. In this topic, our goal is to design new actuators or improve the strength of semiconductor devices by exciting them electrically or with an external electric field.

Selected Publications

  1. N. T. Hung, K. Zhang, V. V. Thanh, Y. Guo, A. A. Puretzky, D. B. Geohegan, J. Kong, S. Huang and R. Saito, Nonlinear optical responses of Janus MoSSe/MoS2 heterobilayers optimized by stacking order and strain, ACS Nano 17, 19877-19886 (2023)
  2. N. T. Hung, A. R. T. Nugraha, T. Yang, Z. Zhang and R. Saito, Thermoelectric performance of monolayer InSe improved by convergence of multivalley bands, J. Appl. Phys. 125, 082502 (2019).
  3. N. T. Hung, A. R. T. Nugraha and R. Saito, Two-dimensional MoS2 electrochemical actuator, J. Phys. D: Appl. Phys. 51, 075306 (2018).
  4. N. T. Hung, A. R. T. Nugraha and R. Saito, High-performance three-dimensional carbon Archimedean lattices electromechanical actuators, Carbon 125, 472-479 (2017).
  5. N. T. Hung, A. R. T. Nugraha and R. Saito, Charge-induced electrochemical actuation of armchair carbon nanotube bundles, Carbon 118, 278-284 (2017).