Doping effects of Ru on Sb2Te and Sb2Te3 as phase change materials studied by first-principles calculations

Zhao, Zong‐Yan; Peng, Shuo; Tan, Zhilong; Wang, Chuanjun; Wen, Ming

doi:10.1016/j.mtcomm.2022.103669

Cited by 5 publications

(8 citation statements)

References 38 publications

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“…On this basis, the formation energy of C doping in an FCC-Sb 2 Te 3 was calculated and compared. The Equation for calculating the formation energy of C doping is as follows [ 15 , 20 , 21 , 25 ]:

where

and

are the total energies of a supercell with and without C doping, respectively, and

represents the number of doped atoms.

means adding atoms to the supercell,

means removing atoms from the supercell, and

means the chemical potential of i substance.…”

Section: Resultsmentioning

confidence: 99%

“…We use the Vienna ab initio simulation package (VASP) for density functional theory calculation. We adopted the projector augmented wave (PAW) potentials for describing the ion–electron interaction, the generalized gradient approximation (GGA) of Perdew-Burke–Ernzerhof (PBE) for exchange–correlation interactions between electrons [ 15 , 19 , 20 , 21 , 22 , 23 ]. The calculated valence electrons include 2s 2 2p 2 of C, 5s 2 5p 3 of Sb, and 5s 2 5p 4 of Te, and the plane wave cutoff energy is set to 550 eV.…”

Section: Calculations and Experimental Sectionmentioning

confidence: 99%

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The Effect of Carbon Doping on the Crystal Structure and Electrical Properties of Sb2Te3

Zhang

Rong

et al. 2023

Nanomaterials

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As a new generation of non-volatile memory, phase change random access memory (PCRAM) has the potential to fill the hierarchical gap between DRAM and NAND FLASH in computer storage. Sb2Te3, one of the candidate materials for high-speed PCRAM, has high crystallization speed and poor thermal stability. In this work, we investigated the effect of carbon doping on Sb2Te3. It was found that the FCC phase of C-doped Sb2Te3 appeared at 200 °C and began to transform into the HEX phase at 25 °C, which is different from the previous reports where no FCC phase was observed in C-Sb2Te3. Based on the experimental observation and first-principles density functional theory calculation, it is found that the formation energy of FCC-Sb2Te3 structure decreases gradually with the increase in C doping concentration. Moreover, doped C atoms tend to form C molecular clusters in sp2 hybridization at the grain boundary of Sb2Te3, which is similar to the layered structure of graphite. And after doping C atoms, the thermal stability of Sb2Te3 is improved. We have fabricated the PCRAM device cell array of a C-Sb2Te3 alloy, which has an operating speed of 5 ns, a high thermal stability (10-year data retention temperature 138.1 °C), a low device power consumption (0.57 pJ), a continuously adjustable resistance value, and a very low resistance drift coefficient.

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where

and

are the total energies of a supercell with and without C doping, respectively, and

represents the number of doped atoms.

means adding atoms to the supercell,

means removing atoms from the supercell, and

means the chemical potential of i substance.…”

Section: Resultsmentioning

confidence: 99%

Section: Calculations and Experimental Sectionmentioning

confidence: 99%

The Effect of Carbon Doping on the Crystal Structure and Electrical Properties of Sb2Te3

Zhang

Rong

et al. 2023

Nanomaterials

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“…As Ru is substituted for Fe on the A‐site, our analysis shows that the O 2p band center from the RuO 6 octahedra framework has larger overlap with the Ru 4d band center upshifted farther away from the Fermi level energy and generally narrows the energy gap between the Ru 4d and O 2p band centers. [ 42 ] The states below the fermi level energy while transitioning from FNO to FRNO or RNO have a larger oxygen strength; thus, indicating a higher covalency of the RuO bond in FRNO or RNO, as the fermi level energy moves down in energy and closer to the O 2p states. The operando Ru‐K‐edge EXAF at a higher applied potential of 1.49 V (vs RHE) and O 2p band center calculated of FRNO/CC indicates the upshift of the O 2p band center promoting the development of Ru vacancy sites (Figure 5o).…”

Section: Resultsmentioning

confidence: 99%

Ruthenium Engineered A₂B₂O₆‐Hybrid Columbite Ferrite for Bifunctional pH‐Universal Water Splitting

Bacirhonde

Mohamed

Han

et al. 2023

Advanced Energy Materials

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Single‐atomic catalysts based on ruthenium have a balanced efficiency for water splitting, but it is necessary to control their activity and durability. In this work, a binder‐free Fe2‐xRuxNb2O6 (FRNO) hybrid catalyst is rationally designed through a facile hydrogel‐crosslinking route. The as‐prepared FRNO catalyst exhibits high electrocatalytic activity and stability when operating under acidic (0.5 m H2SO4) and alkaline (1 m KOH) media. Operando X‐ray adsorption and density functional theory calculations show that FRNO/CC, with its high intrinsic conductivity, promotes the adsorption and dissociation of water on its surface by regulating the charge distribution via charge transfer to the coordinated surface oxygen. This facilitates the oxygen evolution reaction (OER) performance by stabilizing *OOH adsorption on Ru and Fe. The FRNO/carbon cloth (CC) hybrid catalyst also delivers excellent activity and stability for both hydrogen evolution reaction (HER) and OER in pH‐universal electrolytes with low overpotentials of 30 mV per 82 mV for HER and 200 mV per 260 mV for OER at a current density of 10 mA cm‐2 in acidic/basic medium. Ultimately, the FRNO/CC hybrid catalyst shows good water‐splitting performance, and it is expected to help contribute to the creation of various hybrid electrocatalysts.

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“…Among the nonvolatile memories, phase change memory (PCM) has been regarded as a potential next-generation non-volatile memory because of its edge of high scalability, faster operation speed and good durability [5][6][7][8][9][10]. The principle relies on the transition between the amorphous and crystalline state and is embodied in the application of a long low current pulse (SET) to put the PCM device in a low resistance crystalline state, followed by a short high current pulse (RESET) to put the device in a high resistance amorphous state [11][12][13][14].…”

Section: Introductionmentioning

confidence: 99%

Superlattice-like Sb₇₀Se₃₀/HfO₂ thin films for high thermal stability and low power consumption phase change memory

Wang

Chen

2023

Nanotechnology

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We have fabricated Sb70Se30/HfO2 superlattice-like (SLL) structure thin films for phase change memory by magnetron sputtering method, and investigated the effect of the HfO2 layer on the crystalline characteristics and phase change behavior of Sb70Se30/HfO2 thin films. The experimental results show that as the HfO2 thickness increases, the crystallization temperature rises, the data retention capacity increases as well as the band gap widens, which is beneficial for improving the thermal stability and reliability of Sb70Se30/HfO2 thin films. It was also found that the HfO2 composite layer inhibited the grain growth of the Sb70Se30 thin film, reducing the grain size and resulting in a smoother surface. In addition, the volume fluctuation of the Sb70Se30/HfO2 thin films changes by only 5.58 % between amorphous and crystalline. The threshold and reset voltages of the cell based on Sb70Se30/HfO2 thin films are 1.52 V and 2.4 V respectively. We found that the HfO2 composite layer plays a significant role in improving thermal stability, refining grain size of Sb70Se30 phase change films and reducing device power consumption.

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Doping effects of Ru on Sb2Te and Sb2Te3 as phase change materials studied by first-principles calculations

Cited by 5 publications

References 38 publications

The Effect of Carbon Doping on the Crystal Structure and Electrical Properties of Sb2Te3

The Effect of Carbon Doping on the Crystal Structure and Electrical Properties of Sb2Te3

Ruthenium Engineered A₂B₂O₆‐Hybrid Columbite Ferrite for Bifunctional pH‐Universal Water Splitting

Superlattice-like Sb₇₀Se₃₀/HfO₂ thin films for high thermal stability and low power consumption phase change memory

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Doping effects of Ru on Sb2Te and Sb2Te3 as phase change materials studied by first-principles calculations

Cited by 5 publications

References 38 publications

The Effect of Carbon Doping on the Crystal Structure and Electrical Properties of Sb2Te3

The Effect of Carbon Doping on the Crystal Structure and Electrical Properties of Sb2Te3

Ruthenium Engineered A2B2O6‐Hybrid Columbite Ferrite for Bifunctional pH‐Universal Water Splitting

Superlattice-like Sb70Se30/HfO2 thin films for high thermal stability and low power consumption phase change memory

Contact Info

Product

Resources

About

Ruthenium Engineered A₂B₂O₆‐Hybrid Columbite Ferrite for Bifunctional pH‐Universal Water Splitting

Superlattice-like Sb₇₀Se₃₀/HfO₂ thin films for high thermal stability and low power consumption phase change memory