Robust Metal-Insulator Transition Despite Surface Dead-Layer Growth in Sub-10-nm Cr-Doped V2O3 Nanocrystals
Yoichi Ishiwata, Ichidai Harada, Masaki Imamura, Kazutoshi Takahashi, Hirofumi Ishii + 7 more
TLDR
Cr-doped V2O3 nanocrystals maintain their metal-insulator transition down to 5.6 nm, despite surface dead-layer growth.
Key contributions
- MIT signatures persist in Cr-doped V2O3 nanocrystals down to an average size of 5.6 nm.
- Magnetic susceptibility measurements exhibit a nearly size-invariant transition onset.
- The metal-insulator transition survives in the nanocrystal interior despite growing surface dead layers.
- Nanoscaling progressively enhances surface-driven insulating behavior, suppressing quasiparticle weight.
Why it matters
This paper demonstrates that the metal-insulator transition in Mott materials can be miniaturized further than previously thought. It provides crucial insights into the practical limits of scaling down Mott-based devices, which are important for next-generation electronics.
Original Abstract
We investigated the size dependence of the metal-insulator transition (MIT) in Cr-doped V2O3 nanocrystals by photoemission spectroscopy using complementary probing depths, together with magnetic susceptibility measurements. Photoemission spectra show that MIT signatures persist down to an average particle size of 5.6 nm, and magnetic susceptibility measurements exhibit a nearly size-invariant transition onset. The contrast between surface-sensitive and deeper-probing photoemission spectra reveals that the transition survives in the nanocrystal interior. At the same time, the spectra indicate a systematic suppression of coherent quasiparticle weight with decreasing size, pointing to the growth of an insulating surface dead layer. These results demonstrate that nanoscaling does not intrinsically eliminate the MIT itself, but progressively enhances the influence of surface-driven insulating behavior, thereby providing insight into the practical limits of miniaturizing Mott-based devices.
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