Reversible Switching of FePc Molecule Structure on BiAg₂ Rashba Surface Alloy

Nitin Kumar^1*, Yen-Hui Lin¹, Cheng-Yu He¹, Jun-Quan Xiao¹, Hung-Chin Lee¹, Pin-Jui Hsu^1,2

¹Department of Physics, National Tsing Hua University, Hsinchu, Taiwan
²Center for Quantum Technology, National Tsing Hua University, Hsinchu, Taiwan

* Presenter:Nitin Kumar, email:itsnitin95@gmail.com

Molecular magnets absorbed on surfaces with strong spin-orbital coupling (SOC) are of great interest for exploring novel phenomena and applications in spintronics and molecular electronics. In this work, Iron phthalocyanine (FePc) molecules absorbed on BiAg₂/Ag(111) Rashba surface alloy have been studied under scanning tunneling microscopy (STM). A new stable structure of FePc molecule with a six-lobe appearance in STM topographs has been observed in contrast with the typically observed four-lobe structure. More interestingly, a bias voltage pulse-induced reversible switching between six- and four-lobe structures has been perceived. As well as a precisely controlled vice-versa switching between these two states has been demonstrated using an STM tip. Additionally, spatially resolved molecular orbitals for both structures have been recorded in high quality. Our findings suggest that the new structure of the FePc might be stemming from a special hybridization between the molecule and √3×√3 structure of BiAg₂ Rashba surface and two-state bistability as a result of the double-well potential behavior of the system.

Keywords: Iron Phthalocyanine (FePc), Scanning Tunneling Microscopy (STM), Rashba surface alloy, Molecular structure switching, Spin-orbital coupling