Kavli Affiliate: Gang Su
| First 5 Authors: Qing-Han Yang, Qing-Han Yang, , ,
| Summary:
The development of room-temperature magnetic semiconductors is critical for
advancing spintronic technologies, yet van der Waals magnets like CrI3 exhibit
intrinsically low Curie temperatures (Tc = 45 K). This study employs
first-principles calculations to demonstrate that atom intercalation,
particularly lithium (Li), dramatically enhances magnetic exchange couplings in
CrI3, achieving near room-temperature ferromagnetism with a predicted Tc of 286
K-aligning with experimental reports of 420 K. The underlying mechanism
involves synergistic superexchange and double-exchange interactions:
intercalation reduces the |Ep-Ed| energy difference between iodine p-orbitals
and chromium d-orbitals, strengthening superexchange pathways, while charge
transfer induces valence mixing (e.g., Cr3+ to Cr2+, as confirmed by
experimental X-ray photoelectron spectrometry data), promoting double-exchange.
Theoretical predictions extend to other intercalants including Cu and Na, with
Cu0.25CrI3 and Na0.25CrI3 exhibiting Tc of 267 K and 247 K, respectively,
establishing a versatile strategy for designing high-Tc magnetic
semiconductors. This work bridges theoretical insights with experimental
validation, offering a transferable framework for intercalation-driven material
design and accelerating practical spintronic device realization.
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