[15a-P6-1~13] 6.5 Surface Physics, Vacuum

[15a-P6-13] Scanning tunneling spectroscopy evaluation by a simple model

〇Kazuki Kusanagi¹, Tatsuya Okazaki¹, Jinwoo Park¹, Yuki Sato¹, Yoshinobu Ogawa¹, Hideo Matsuyama¹ (1.Hokkaido Univ.)

Keywords:Scanning tunneling microscopy, SN ratio, dI/dV

When measuring the local state density (LDOS) of a sample by using a scanning tunneling microscope (STM), we often superimpose a modulation voltage on a bias voltage and detect the signal by using lock-in method. However, there is a stray capacitance between the probe and the sample, and this effect is superimposed on the output of the lock-in amplifier. In this study, we treat the probe - sample in the detection system as a simple model with resistance R_s and stray capacitance C_s, and discuss the SN ratio of the detection signal. We also propose a simple method to cancel current flowing through C_s.