Radio frequency reflectometry scanning tunneling microscopy
Woei Wu Pai1*, I. J. Chan1, Y. C. Chao1, H. H. Li1
1Center for condensed matter sciences, National Taiwan University, Taipei, Taiwan
* presenting author:Woei Wu Pai, email:wpai@hotmail.com
In this talk, I introduce a new patented scanning probe microscopy technique, named radio frequency reflectometry scanning tunneling microscopy (RFSTM). I will summarize the current development status of this instrumentation project and present the needed hardware, electronics, and software. In RFSTM, a tunneling junction is a part of a sensitive RF resonance tank circuit. A change of the tunneling junction impedance leads to a change of RF reflectivity. RFSTM can detect a ~ -100 dB change in RF reflectivity, which corresponds to ~GΩ junction resistance. We show that RFSTM can achieve a detection bandwidth of ~500 MHz far exceeding the ~100 kHz of a conventional I-V converter. RFSTM also achieves atomic resolution and yields better contrast than conventional STM. Furthermore, RFSTM detection is insensitive to perturbation from external electron sources. Therefore, RFSTM can be used in conjunction with electron or X-ray beams for in-situ studies.


Keywords: radio frequency, STM, reflectometry, instrumentation