Strong Defect-Site-Dependence of Quasiparticle Scattering Channels Observed in a Dirac Semimetal Using Stm
Christopher J. Butler1*, Yu-Mi Wu1, Cheng-Rong Hsing2, Raman Sankar3,4, Yi Tseng1, Ching-Ming Wei2, Fang-Cheng Chou4,5,6, Minn-Tsong Lin1,2,7
1Department of Physics, National Taiwan University, Taipei, Taiwan
2Institute of Atomic and Molecular Sciences, Academia Sinica, Taipei, Taiwan
3Institute of Physics, Academia Sinica, Taipei, Taiwan
4Center for Condensed Matter Sciences, National Taiwan Unviersity, Taipei, Taiwan
5National Synchrotron Radiation Research Center, Hsinchu, Taiwan
6Taiwan Consortium of Emergent Crystalline Materials (TCECM), Ministry of Science and Technology, Taipei, Taiwan
7Research Center for Applied Sciences, Academia Sinica, Taipei, Taiwan
* presenting author:Christopher Butler, email:cjbutler@ntu.edu.tw
Observations of quasiparticle interference patterns extend the purview of STM into momentum space, allowing insights complementary to those of band structure mapping techniques such as ARPES. Moreover, the un-rivaled spatial resolution of STM allows further glimpses of the detailed interactions of quasiparticles with atomic scale features, such as impurities and other point defects, far beyond the resolution limit of other techniques. Here we report atomically resolved STM topography and tunneling spectro-microscopy measurements on the Dirac nodal-line semimetal zirconium silicon sulfide. These measurements reveal a strong selectivity of quasiparticle scattering channels in momentum space, depending on the lattice site of the impurity scattering center. We attempt to explain this unusual selectivity with support from ab initio band calculations. Several possible mechanisms connecting particular quasiparticle bands to real-space lattice sites will be discussed. Aside from the current case, this observation may provide insights into quasiparticle scattering which extend more generally to numerous material systems.

This project is financially sponsored by Ministry of Science and Technology (MOST 105-2119-M-002-013)


Keywords: scanning tunneling microscopy, quasiparticle interference, point defects, defect-dependent scattering, Dirac semimetal