Detecting signatures of surface antibonding nodes through atomic-scale thermopower

Atomic-scale thermopower connotes rich physics of wave functions based on quantum transport characteristics. Previous studies revealed that vestiges of wave function could be utilized for the nanoscale thermopower domain. However, how the disappearance of wave function would be represented in coherent thermopower remains to be elucidated. In this paper, using first-principles-based scanning Seebeck microscopy, we demonstrate that atomic-scale thermopower sensitively responds to antibonding nodal lines. Utilizing the linear tetrahedron method (LTM), we validate the fidelity of local thermopower even with relatively sparse k-points sampling. Notably, the LTM furnishes reasonable thermopower evaluation near the singular points in the density of states. Our calculations identified that the next-nearest eigenstate from the Fermi level provokes sudden variations of thermopower profiles near antibonding nodal lines. Direct comparison with scanning tunneling microscopy simulation has pointed out the distinguished node-detection competence of local thermopower. We believe that this study highlights the unique potential of coherent thermopower as a tool to unearth fundamental information about wave function overlap not to be measured before.