Scanning Tunneling Microscope Tip-Induced Formation of Bi Bilayers on Bi$_2$Te$_3$

Fuente: arXiv
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Main Authors: Nguyen, Duy, Gupta, Jay A.
Format: Preprint
Published: 2025
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author Nguyen, Duy
Gupta, Jay A.
author_facet Nguyen, Duy
Gupta, Jay A.
contents We report the formation of Bi(111) bilayer (BL) islands and crater structures on Bi$_2$Te$_3$(111) surfaces induced by voltage pulses from an STM tip. Pulses above a threshold voltage ($+3$ V) produce craters $\sim 0.5$ microns in diameter, similar to the size of the tip. Redeposited material self-assembles into a network of atomically ordered islands with a lattice constant identical to the underlying Bi$_2$Te$_3$ surface. The island size monotonically decreases over several microns from the pulse site, until the pristine Bi$_2$Te$_3$ surface is recovered. We assign these islands to Bi BL based on atomic resolution images, analysis of step heights, and tunneling spectroscopy. The dependence of bilayer formation on bias polarity and the evidence for defect diffusion together suggest a mechanism driven by the interplay of field evaporation and tunneling-current-induced Joule heating.
format Preprint
id arxiv_https___arxiv_org_abs_2507_16081
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Scanning Tunneling Microscope Tip-Induced Formation of Bi Bilayers on Bi$_2$Te$_3$
Nguyen, Duy
Gupta, Jay A.
Mesoscale and Nanoscale Physics
Materials Science
We report the formation of Bi(111) bilayer (BL) islands and crater structures on Bi$_2$Te$_3$(111) surfaces induced by voltage pulses from an STM tip. Pulses above a threshold voltage ($+3$ V) produce craters $\sim 0.5$ microns in diameter, similar to the size of the tip. Redeposited material self-assembles into a network of atomically ordered islands with a lattice constant identical to the underlying Bi$_2$Te$_3$ surface. The island size monotonically decreases over several microns from the pulse site, until the pristine Bi$_2$Te$_3$ surface is recovered. We assign these islands to Bi BL based on atomic resolution images, analysis of step heights, and tunneling spectroscopy. The dependence of bilayer formation on bias polarity and the evidence for defect diffusion together suggest a mechanism driven by the interplay of field evaporation and tunneling-current-induced Joule heating.
title Scanning Tunneling Microscope Tip-Induced Formation of Bi Bilayers on Bi$_2$Te$_3$
topic Mesoscale and Nanoscale Physics
Materials Science
url https://arxiv.org/abs/2507.16081