Electromigration in nanostructures made of lead and tin

• Grant number: 25/03840-7
• Support Opportunities: Scholarships in Brazil - Master
• Start date: May 01, 2025
• End date: April 30, 2027
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Maycon Motta
• Grantee: Marcos Vasconcellos Mistura
• Host Institution: Centro de Ciências Exatas e de Tecnologia (CCET). Universidade Federal de São Carlos (UFSCAR). São Carlos , SP, Brazil
• Associated research grant: 22/03124-1 - Electromigration in nanostructures, AP.PNGP.PI

Abstract

Superconductivity is a vital field within condensed matter physics. In the bulky form, lead and tin are classified as type I superconductors, with critical temperatures of 7.2 K and 3.7 K, respectively. However, when dimensions are reduced to the scale of hundreds of nanometers, thin films of these materials exhibit type II superconducting behavior, enabling vortex penetration. Within constrictions made from these thin films, a phenomenon known as electromigration (EM) occurs, driven by electron drag forces from sufficiently high current densities that can displace individual atoms within the crystal lattice. In our project, we plan to create thin films of these low-melting-point metals (Pb and Sn) with varying grain sizes by adjusting the substrate temperature during deposition and potentially through subsequent heat treatment. Following this, we will construct devices with different constriction geometries to explore how device structure affects the distribution of current lines and EM characteristics. Additionally, we will study the anti-electromigration effect by reversing the polarity of the applied current in these same devices. This approach will allow us to examine the influence of initial granularity on both electromigration and the superconducting state. Ultimately, this work aims to enhance our understanding of how these variables impact atomic migration due to electric current.