Unraveling the Atomic Structure of Bulk Binary Ga–Te Glasses with Surprising Nanotectonic Features for Phase-Change Memory Applications
Résumé
Binary Ge−Te and ternary Ge−Sb−Te systems belong to flagship phasechange materials (PCMs) and are used in nonvolatile memory applications and neuromorphic computing. The working temperatures of these PCMs are limited by low-T glass transition and crystallization phenomena. Promising high-T PCMs may include gallium tellurides; however, the atomic structure and transformation processes for amorphous Ga−Te binaries are simply missing. Using high-energy X-ray diffraction and Raman spectroscopy supported by first-principles simulations, we elucidate the shortand intermediate-range order in bulk glassy Ga x Te 1−x , 0.17 ≤ x ≤ 0.25, following their thermal, electric, and optical properties, revealing a semiconductor−metal transition above melting. We also show that a phase change in binary Ga−Te is characterized by a very unusual nanotectonic compression with the high internal transition pressure reaching 4−8 GPa, which appears to be beneficial for PCM applications increasing optical and electrical contrast between the SET and RESET states and decreasing power consumption.
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Licence : CC BY ND - Paternité - Pas de modifications
Licence : CC BY ND - Paternité - Pas de modifications