Flat Bands Boost Metallic Thermoelectrics

Date

Sep 16, 2025

Time

9:00 AM - 10:00 AM

Speaker

Associate Prof. Dr. Andrej Pustogow

Affiliation

TU Wien, Austria

Language

en

Main Topic

Materialien

Host

Martina Javorka

Description

Thermoelectric (TE) materials directly transform thermal into electrical energy and vice versa, making them promising for applications in cooling or power generation. However, state-of-the-art semiconductors in the focus of current research so far have not made the leap into broad applications due to low power density and poor mechanical properties. Metallic materials would be superior in this regard, but remained largely neglected over the past decades due to their small Seebeck coefficient S. Here we realize ultrahigh TE performance in metals via tuning of electronic interband scattering – an innovative enhancement principle cardinally different from those applied in semiconductors so far. In particular, we boost S by selectively reducing the mobility of holes as they scatter off localized states, leveraged by electronic bandwidth tuning. Using this paradigm, we recently discovered record-high power factors (PF) of 34 mWm-1K-2 in binary NixAu1-x alloys. Despite this unprecedented TE performance (highest zT almost equal to 0.5 among all metals), metastability and high cost of NixAu1-x pose difficulties for applications. We have therefore continued our quest for metallic TE with superior functional properties from more abundant elements. Utilizing an automated materials screening approach, we discover ultrahigh PF up to 11 mWm-1K-2 near room temperature in the textbook metal Ni3Ge. In our quest for novel physical mechanisms to tailor electronic scattering, we identify frustration-induced topological flat bands as an extremely effective tool to boost the performance of metallic TE.

Links

• Seminars at the IFW

Last modified: Sep 16, 2025, 7:36:46 AM