3-Omega technique at low temperatures in complex structures

• Grant number: 24/23507-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: April 01, 2025
• End date: December 31, 2025
• Field of knowledge: Physical Sciences and Mathematics - Physics - Condensed Matter Physics
• Principal Investigator: Valentina Martelli
• Grantee: André Gonçalves Costa
• Host Institution: Instituto de Física (IF). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 18/19420-3 - Thermoelectricity and heat transport in topological materials, AP.JP

Abstract

In the framework of the main project that hosts this IC project, we have been investigating the thickness-dependence thermal transport in complex oxides and in materials hosting a topological insulating state to explore the effect on both thermal and thermoelectric properties when a material undergoes structural distortions or change in the protected conducting surfaces, respectively. The 3Omega technique is established and is appropriate for measuring thermal conductivity both in bulk and thin films. However, it poses several challenges. One of those is the extension to low temperatures (T < 50 K), which is limited by the typical use of metallic (e.g. Ag, Au, Pt) as a temperature transducer. In this work, we will study the adaptation of the model of the 3Omega technique at lower temperatures when candidate resistances with a non-linear response in temperature are employed. Furthermore, we will grow Zr-based thin films to test as alternative transducers.