Electron localization engineering in entropy-mediated heterostructures for amplifying interfacial polarization

Electron localization engineering via Fe/Cr doping tailors work function differences to amplify dielectric loss in M 3 S 4 /MS-type and M 9 S 8 /MS-type heterostructures. • Entropy-mediated Fe/Cr doping causes the different heterostructures compositions and regulated electron localization capabilities to modulate the work functions of phases, maximizing work function difference to 1.46 eV. • Entropy-mediated Fe/Cr co-doping achieves −46.57 dB reflection loss and 4.40 GHz bandwidth, elucidating entropy-mediated doping via electron localization for amplifying interfacial polarization. Interfacial polarization governed via work function differences offers a critical avenue for amplifying dielectric loss. However, in entropy-mediated heterogeneous systems, the underlying electron-structure principles that manipulating work functions remains unraveled, hindering interfacial polarization maximization. Herein, we exploit entropy-mediated Fe/Cr doping to tailor electron localization characteristics in medium-/high-entropy sulfide heterostructures. It is noted that Fe-doped samples form M 3 S 4 /MS heterostructures, while Cr-doped and Fe/Cr co-doped samples adopt M 9 S 8 /MS heterostructures, where the electron localization of Fe-related electrons is higher compared to Cr. The different heterostructures compositions and regulated electron localization capabilities modulate the work functions of phases. This elective doping creates a stepwise increase in interfacial work function difference from 0.91 eV (Fe-doped quaternary M 3 S 4 /MS-type pair) to 1.14 eV in Cr-doped quaternary M 9 S 8 /MS-type interface. Finally this difference reaches maximum of 1.46 eV in consistent M 9 S 8 /MS-type quinary heterostructure (CoNiFeCrAl-S, 5-HES), amplying interfacial polarization loss. The increase of metal species secondarily enhance vacancy-induced dipole polarization and slightly enhance conduction loss. Therefore, these effects award 5-HES yield a improved reflection loss (−46.57 dB) and an effective absorption bandwidth (4.40 GHz). This work elucidates the mechanistic role of entropy-mediated doping in work function tuning through electron localization within this sulfide system, providing electronic-structure insights for doping-based electromagnetic heterostructures to amplify interfaces effect. Download: Download high-res image (444KB) Download: Download full-size image