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HL: Fachverband Halbleiterphysik
HL 41: Quantum Dots and Point Contacts (joint session TT/HL)
HL 41.5: Vortrag
Donnerstag, 12. März 2026, 12:00–12:15, HSZ/0101
Spectroscopic-imaging Coulomb blockade microscopy — Junho Bang1, Byeongin Lee1, Hankyu Lee1, •Jianfeng Ge2, and Doohee Cho1 — 1Department of Physics, Yonsei University, Seoul 03722, Republic of Korea — 2Max Planck Institute for Chemical Physics of Solids, 01187 Dresden, Germany
We use scanning tunneling microscopy (STM) to directly visualize Coulomb blockade (CB) phenomena in the double-barrier tunnel junction formed between the STM tip and crystalline indium nanoislands on semiconducting black phosphorus. Spatially resolved tunneling spectra reveal bias-dependent dispersions of CB peaks across individual nanoislands. Strikingly, the trajectories of CB peaks exhibit two-fold asymmetries: (i) their curvatures reverse sign across a nonzero bias offset, and (ii) the trajectories lack mirror symmetry about this bias offset. Simulations based on orthodox theory faithfully reproduce both asymmetries, which we trace to work-function mismatches at (i) the island-tip and (ii) the island-substrate interfaces, respectively. These results establish spectroscopic-imaging Coulomb-blockade microscopy as a quantitative probe of junction parameters, offering a pathway for diagnosing and optimizing single-electron charge sensors relevant to quantum-computing architectures.
Keywords: Coulomb blockade; work function; scanning tunneling microscopy; nanoisland