Anomalous Glassy Thermal Conductivity in a Perovskite Bismuthate Induced by Structural Dynamic Instability

Author(s)

Henriques, Alexandre ; Lima, Mariana S. L. ; Nilsen, Goran J. ; Gutmann, Matthias J. ; Wirth, Steffen ; Brito, Walber H. ; Martelli, Valentina

• Document type: Journal article
• Source: ADVANCED SCIENCE; v. N/A, p. 10-pg., 2025-06-04.

Abstract

Unraveling the underlying mechanisms at the origin of ultra-low thermal conductivity in pristine crystals is of central relevance to designing new functional materials. Here, a study of thermal conductivity kappa(T) in an extended temperature range (1.5-400 K) is reported in the single-crystalline bismuthate perovskite BaBiO3. The measured kappa(T) shows an anomalous glass-like behavior with a approximate to T-2 dependence at low temperatures and a plateau in a wide temperature range from about 20 to 260 K, surprisingly recovering the expected downturn for a crystal only for T > 300 K. The measured room temperature kappa approximate to 1.6 W m(-1) K-1 agrees with the calculated value, including three-phonon and isotope disorder scattering. However, the departure of the experimental from the calculated kappa(T) for T < 300 K, at the onset of the plateau, indicates that an additional scattering mechanism comes into play at lower temperatures. It is proposed that a tunneling two-level system associated with the BiO6 octahedra rotation offers an additional phonon scattering mechanism and may explain the observed kappa(T) suppression. The findings may have significant implications for the pairing mechanism and unconventional superconductivity of doped-BaBiO3 aside from suggesting it as a candidate building block for functional heterostructures. (AU)

• FAPESP's process: 21/00989-9 - Investigation of thermal transport in low-dimensional complex oxides
• Grantee: Alexandre Henriques da Silva
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 24/00177-2 - Thermoelectricity in topological crystalline Insulators: from bulk to thin films
• Grantee: Mariana Saraiva Leão Lima
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 22/01742-0 - Investigation of thermal transport in complex oxides towards low-dimensionality
• Grantee: Alexandre Henriques da Silva
• Support Opportunities: Scholarships in Brazil - Doctorate (Direct)
• FAPESP's process: 22/14202-3 - Novel states of quantum matter under extreme conditions
• Grantee: Julio Antonio Larrea Jimenez
• Support Opportunities: Regular Research Grants
• FAPESP's process: 18/19420-3 - Thermoelectricity and heat transport in topological materials
• Grantee: Valentina Martelli
• Support Opportunities: Research Grants - Young Investigators Grants
• FAPESP's process: 18/08845-3 - An investigation into topological and exotic quantum states under extreme conditions (InvestInTopQuantEx)
• Grantee: Julio Antonio Larrea Jimenez
• Support Opportunities: Research Grants - Young Investigators Grants
• FAPESP's process: 19/17874-0 - Multi-user Equipmente approved in grant 2013/08293-7, KAHUNA upgrade - HPE Apollo Gen10 supercomputer
• Grantee: Munir Salomao Skaf
• Support Opportunities: Multi-user Equipment Program
• FAPESP's process: 24/16100-9 - What is the minimal condition for a phonon to couple to a magnetic field and bend its trajectory?
• Grantee: Valentina Martelli
• Support Opportunities: Regular Research Grants