[2D12-21] Surface Science (SS1) Physical Property

5:00 PM - 5:15 PM JST(8:00 AM - 8:15 AM UTC)

[2D21] Annihilation of Subsurface Ar Nanobubbles in Pb(111) via High-Temperature Sputtering

*Naoya Kawakami¹, Noriaki Takagi², Chun-Liang Lin¹ (1. National Yang-Ming Chiao-Tung University (Taiwan), 2. Graduate School of Human and Environmental Studies, Kyoto University (Japan))

Pb(111) is vital for quantum research, but conventional room-temperature Ar+ sputtering and annealing leave stable subsurface Ar nanobubbles. These bubbles modulate the electronic structure via quantum confinement, hindering accurate measurements. We developed a novel protocol to eliminate these bubbles by elevating the sputtering temperature to 513 K, thereby reducing the residual bubble density by over 90%. Combining STM and dZ/dV spectroscopy, we reconstructed the 3D depth distribution of Ar atoms. The distribution showed a bimodal profile, revealing that high-temperature sputtering selectively suppresses "shallow bubble" formation. This suppression is driven by a synergistic effect: kinetic desorption from enhanced Ar mobility, and physical milling by ion bombardment. This methodology yields exceptionally pristine Pb(111) surfaces and offers a robust strategy for defect engineering in nanomaterials.

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