Atypical phase-change alloy Ga₂Te₃: atomic structure, incipient nanotectonic nuclei, and multilevel writing

Abstract

Emerging brain-inspired computing needs phase-change materials of the next generation with lower energy consumption and wider temperature range. Gallium tellurides appear to be promising candidates enable to achieve the necessary requirements.

Deciphering Fast Ion Transport in Glasses: A Case Study of Sodium and Silver Vitreous Sulfides

“…The tetrahedral shape of GeX 4 entities clearly shows the orientational order parameter q , , Figure a,b, extended beyond the tetrahedral geometry − where ψ jk is the X–Ge–X angle of a given GeX n unit, see also Figure S9 and related more detailed comments. The nontetrahedral fraction is negligible, 2.6%.…”

High-Pressure Synthesis of β- and α-In2Se3-Like Structures in Ga2S3

“…This result opens new possibilities for Ga 2 S 3 to design cheap, nontoxic, nonrare-earth, and abundant-element-based devices for SHG, PWS, ferroelectric, pyroelectric, and piezoelectric applications. Moreover, it will guide further works devoted on other III–VI sesquichalcogenides to synthesize α- and β-In 2 Se 3 -like structures not only at HP but also at RC via existing or emerging 2D materials synthesis methods ,,,,− or by PLD as β′-Ga 2 Te 3 was recently obtained . Finally, we will propose that the second phase observed on decompression shows a DZ structure and therefore is identified with the γ-Ga 2 S 3 phase observed at HT.…”

“…Similarly to defective Ga 2 S 3 phases, the defective nonlayered phases of Ga 2 Se 3 and Ga 2 Te 3 have also been grown in 2D forms: mono-β-Ga 2 Se 3 by chemical close-spaced vapor transport, , low-pressure (LP) CVD, and the sol–gel method; α-Ga 2 Se 3 by molecular beam epitaxy (MBE), , thermal evaporation, and heteroepitaxial growth; and β-Ga 2 Te 3 by LP CVD, , direct synthesis, and PLD . These phases have been used in a number of applications, like in high-performance thermoelectric devices, ,, phase change memories, ,, radiation detectors, , light emitters, , solar-energy devices, ,, SHG, and photocatalytic water splitting (PWS) systems …”

Unexpected Role of Metal Halides in a Chalcogenide Glass Network

“…The FPMD simulations included sample annealing above the glass transition temperature, 56 ps at 500 K for (AgI) 0.1 (As 2 S 3 ) 0.9 and 32 ps at 450 K for (AgBr) 0.5 (As 2 S 3 ) 0.5 , using a Nosé-Hoover thermostat chain controlling the temperature [36,37] and the final modeling over 50 ps or 38 ps at 300 K for the two systems, respectively. Further FPMD details can be found in Supplementary material, including Figures S3 and S4, and elsewhere [38][39][40].…”

“…First neighbor interatomic distances r and partial coordination numbers Nij in (AgI) 0.1 (As 2 S 3 ) 0.9 and (AgBr) 0.5 (As 2 S 3 ) 0.5 glasses.. chemical disorder in chalcogenide glassy systems seems to be a common feature of FPMD simulations using PBE or PBEsol and requires the use of advanced hybrid functionals, TPSS [76,77], BLYP [78][79][80] or PBE0 [38][39][40], to improve the agreement with experiments. Nevertheless, the simulated partial functions reflect reasonably well the diffraction results.…”