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Updated: Jun 15, 2025
08:45
Fabrication of Spatially Confined Complex Oxides
Published on: July 1, 2013
9.5K
Tuning the Spin Transition and Carrier Type in Rare-Earth Cobaltates via Compositional Complexity.
Alan Zhang1, Sangheon Oh1, Byoung Ki Choi2,3
1Sandia National Laboratories, 7011 East Ave., Livermore, CA, 94550, USA.
Advanced Materials (Deerfield Beach, Fla.)
|August 24, 2024
Summary
Compositional complexity in oxides offers a new way to engineer material properties. This study shows tunable complexity improves semiconductor performance and enables novel doping methods.
Area of Science:
- Materials Science
- Solid-State Chemistry
- Semiconductor Physics
Background:
- Growing interest in materials with engineered properties beyond traditional limits.
- Compositionally complex oxides (CCOs), or high entropy oxides, form single-phase solid solutions with unique characteristics.
- The relationship between compositional complexity and material properties is not fully understood and is challenging to predict.
Purpose of the Study:
- To demonstrate compositional complexity as a tunable parameter in spin-transition oxide semiconductors.
- To investigate the effects of varying rare earth cation populations on material properties.
- To explore novel doping mechanisms in semiconductors.
Main Methods:
- Synthesized a series of La1- x(Nd, Sm, Gd, Y)x/4CoO3 oxides with varying rare earth content (x=0.00–0.80).
- Employed first principles calculations and angle-resolved photoemission spectroscopy.
- Utilized Seebeck measurements to analyze charge carrier behavior.
Main Results:
- Increasing compositional complexity systematically improved crystallinity.
- Observed an increase in electron carriers relative to hole carriers with higher complexity.
- Tuned the spin transition temperature and on-off ratio of the semiconductor.
- Demonstrated a crossover from hole- to electron-majority conduction at high complexity (x=0.8) without conventional donors.
- Identified lattice distortions as an unconventional doping mechanism.
Conclusions:
- Tunable compositional complexity is a facile method to enhance semiconductor properties.
- This approach offers a new route for doping semiconductors beyond traditional techniques.
- Lattice distortions play a key role in the unconventional doping mechanism.
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