Realizing Thermoelectric and Thermistor Bi-functionalities via Triggering Electron Correlations with Lattice-dipole

TL;DR

This study demonstrates that lattice-distorted SrNbxTi1-xO3 films exhibit both high thermoelectric efficiency and thermistor functionalities by leveraging electron correlations and lattice dipoles, opening new avenues for multifunctional thermal sensors.

Contribution

It reveals the coexistence of thermoelectric and thermistor functionalities in SrNbxTi1-xO3 films driven by electron correlations and lattice dipoles, a novel multifunctional approach.

Findings

Maximum thermoelectric power factor exceeds 100 μWcm-1K-2.

Strong temperature-dependent carrier scattering introduces large resistance changes.

Lattice dipoles induce positive temperature dependence in thermistor behavior.

Abstract

Establishing strong electron-correlations not only shed lights on overcoming the trade-off limitations for optimizing thermoelectric materials, but can also introduce new functionalities that extend the vision of conventional thermoelectric applications. Here, we demonstrate that the high thermoelectric and thermistor functionalities coexist in lattice distorted SrNbxTi1-xO3 films with electron correlations between carriers and ordering aligned lattice dipoles. As-grown SrNbxTi1-xO3/SrTiO3 with effectively preserved interfacial strains exhibits cross-plane charge ordering and orbital anisotropy, as indicated by the polarization dependent near edge X-ray absorption fine structures. The resultant coulomb-correlations regulate the carrier transport and enhance the Seebeck coefficient more independently via enlarging the system vibration entropy. As-achieved maximum thermoelectric power factor exceeds 100 uWcm-1K-2 measured in the bulk performance of SrNb0.2Ti0.8O3 (2.2 um)/SrTiO3 (100 um), which is comparable to the best thermoelectric materials for low temperature applications. In addition, the strong temperature dependence of the carrier scattering aroused by the lattice dipoles introduces a positive temperature dependent thermistor transportation behavior with large temperature coefficient of resistance ranging from 30 to 300 K, which is rarely seen in conventional thermistors. Combining both functionalities largely extend the horizon in exploring new Joule sensors for detection of temperature and thermal perturbations across a broad temperature range.