A charge density wave (CDW) is one of the fundamental instabilities of the Fermi surface occurring in a wide range of quantum materials. In dimensions higher than one, where Fermi surface nesting can play only a limited role, the selection of the particular wave vector and geometry of an emerging CDW should in principle be susceptible to controllable manipulation. In this work, we implement a simple method for straining materials compatible with low-temperature scanning tunneling microscopy/spectroscopy (STM/S), and use it to strain-engineer new CDWs in 2H-NbSe2. Our STM/S measurements combined with theory reveal how small strain-induced changes in the electronic band structure and phonon dispersion lead to dramatic changes in the CDW ordering wave vector and geometry. Our work unveils the microscopic mechanism of a CDW formation in this system, and can serve as a general tool compatible with a range of spectroscopic techniques to engineer novel electronic states in any material where local strain or lattice symmetry breaking plays a role.
@article{arxiv.1806.09665,
title = {Atomic-Scale Strain Manipulation of a Charge Density Wave},
author = {Shang Gao and Felix Flicker and Raman Sankar and He Zhao and Zheng Ren and Bryan Rachmilowitz and Sidhika Balachandar and Fangcheng Chou and Kenneth Burch and Ziqiang Wang and Jasper van Wezel and Ilija Zeljkovic},
journal= {arXiv preprint arXiv:1806.09665},
year = {2018}
}