中国物理B ›› 2020, Vol. 29 ›› Issue (11): 116805-.doi: 10.1088/1674-1056/abc0d5

所属专题: SPECIAL TOPIC — Machine learning in condensed matter physics

• • 上一篇    下一篇

Ce Wang(王策)1, Haiwei Li(李海威)2, Zhenqi Hao(郝镇齐)2, Xintong Li(李昕彤)2, Changwei Zou(邹昌炜)2, Peng Cai(蔡鹏)3,†(), Yayu Wang(王亚愚)2,4, Yi-Zhuang You(尤亦庄)5,(), Hui Zhai(翟荟)1,§   

  • 收稿日期:2020-07-02 修回日期:2020-08-07 接受日期:2020-10-14 出版日期:2020-11-05 发布日期:2020-11-03

Machine learning identification of impurities in the STM images

Ce Wang(王策)1, Haiwei Li(李海威)2, Zhenqi Hao(郝镇齐)2, Xintong Li(李昕彤)2, Changwei Zou(邹昌炜)2, Peng Cai(蔡鹏)3, †, Yayu Wang(王亚愚)2,4, Yi-Zhuang You(尤亦庄)5,, ‡, and Hui Zhai(翟荟)1,§   

  1. 1 Institute for Advanced Study, Tsinghua University, Beijing 100084, China
    2 State Key Laboratory of Low Dimensional Quantum Physics, Department of Physics, Tsinghua University, Beijing 100084, China
    3 Department of Physics and Beijing Key Laboratory of Opto-electronic Functional Materials and Micro-nano Devices, Renmin University of China, Beijing 100872, China
    4 Frontier Science Center for Quantum Information, Beijing 100084, China
    5 Department of Physics, University of California, San Diego, California 92093, USA
  • Received:2020-07-02 Revised:2020-08-07 Accepted:2020-10-14 Online:2020-11-05 Published:2020-11-03
  • Contact: Corresponding author. E-mail: pcai@ruc.edu.cn Corresponding author. E-mail: yzyou@ucsd.edu §Corresponding author. E-mail:hzhai@tsinghua.edu.cn
  • Supported by:
    HZ is supported by Beijing Outstanding Scholar Program, the National Key Research and Development Program of China (Grant No. 2016YFA0301600), and the National Natural Science Foundation of China (Grant No. 11734010). YZY is supported by a startup fund from UCSD. PC is supported by the Fundamental Research Funds for the Central Universities, and the Research Funds of Renmin University of China.

Abstract:

We train a neural network to identify impurities in the experimental images obtained by the scanning tunneling microscope (STM) measurements. The neural network is first trained with a large number of simulated data and then the trained neural network is applied to identify a set of experimental images taken at different voltages. We use the convolutional neural network to extract features from the images and also implement the attention mechanism to capture the correlations between images taken at different voltages. We note that the simulated data can capture the universal Friedel oscillation but cannot properly describe the non-universal physics short-range physics nearby an impurity, as well as noises in the experimental data. And we emphasize that the key of this approach is to properly deal with these differences between simulated data and experimental data. Here we show that even by including uncorrelated white noises in the simulated data, the performance of the neural network on experimental data can be significantly improved. To prevent the neural network from learning unphysical short-range physics, we also develop another method to evaluate the confidence of the neural network prediction on experimental data and to add this confidence measure into the loss function. We show that adding such an extra loss function can also improve the performance on experimental data. Our research can inspire future similar applications of machine learning on experimental data analysis.

Key words: scanning tunneling microscope, neural network, attention, data regularization