Vacancy tuned thermoelectric properties and high spin filtering performance in graphene/silicene heterostructures

AbstractThe main contribution of this paper is to study the spin caloritronic effects in defected graphene/silicene nanoribbon (GSNR) junctions. Each step-like GSNR is subjected to the ferromagnetic exchange and local external electric fields, and their responses are determined using the nonequilibrium Green’s function (NEGF) approach. To further study the thermoelectric (TE) properties of the GSNRs, three defect arrangements of divacancies (DVs) are also considered for a larger system, and their responses are re-evaluated. The results demonstrate that the defected GSNRs with the DVs can provide an almost perfect thermal spin filtering effect (SFE), and spin switching. A negative differential thermoelectric resistance (NDTR) effect and high spin polarization efficiency (SPE) larger than 99.99% are obtained. The system with the DV defects can show a large spin-dependent Seebeck coefficient, equal to Ss ⁓ 1.2 mV/K, which is relatively large and acceptable. Appropriate thermal and electronic properties of the GSNRs can also be obtained by tuning up the DV orientation in the device region. Accordingly, the step-like GSNRs can be employed to produce high efficiency spin caloritronic devices with various features in practical applications.

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Pure thermal spin current and perfect spin-filtering with negative differential thermoelectric resistance induced by proximity effect in graphene/silicene junctions

Scientific Reports ◽

10.1038/s41598-020-80616-3 ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Zainab Gholami ◽

Farhad Khoeini

Keyword(s):

Electric Fields ◽

Spin Current ◽

Exchange Field ◽

Electron Current ◽

Thermal Electron ◽

External Electric Fields ◽

Spin Caloritronics ◽

Ferromagnetic Exchange ◽

Threshold Temperatures ◽

Spin Filtering

AbstractThe spin-dependent Seebeck effect (SDSE) and thermal spin-filtering effect (SFE) are now considered as the essential aspects of the spin caloritronics, which can efficiently explore the relationships between the spin and heat transport in the materials. However, there is still a challenge to get a thermally-induced spin current with no thermal electron current. This paper aims to numerically investigate the spin-dependent transport properties in hybrid graphene/silicene nanoribbons (GSNRs), using the nonequilibrium Green’s function method. The effects of temperature gradient between the left and right leads, the ferromagnetic exchange field, and the local external electric fields are also included. The results showed that the spin-up and spin-down currents are produced and flow in opposite directions with almost equal magnitudes. This evidently shows that the carrier transport is dominated by the thermal spin current, whereas the thermal electron current is almost disappeared. A pure thermal spin current with the finite threshold temperatures can be obtained by modulating the temperature, and a negative differential thermoelectric resistance is obtained for the thermal electron current. A nearly zero charge thermopower is also obtained, which further demonstrates the emergence of the SDSE. The response of the hybrid system is then varied by changing the magnitudes of the ferromagnetic exchange field and local external electric fields. Thus, a nearly perfect SFE can be observed at room temperature, whereas the spin polarization efficiency is reached up to 99%. It is believed that the results obtained from this study can be useful to well understand the inspiring thermospin phenomena, and to enhance the spin caloritronics material with lower energy consumption.

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Half-metallicity and high spin-filtering effect of magnetic atoms embedded zigzag 6, 6, 12-graphyne nanoribbon

Carbon ◽

10.1016/j.carbon.2016.11.022 ◽

2017 ◽

Vol 113 ◽

pp. 170-175 ◽

Cited By ~ 18

Author(s):

Chen-Chen Zhao ◽

Shi-Hua Tan ◽

Yan-Hong Zhou ◽

Rong-Ji Wang ◽

Xin-Jun Wang ◽

...

Keyword(s):

High Spin ◽

Half Metallicity ◽

Filtering Effect ◽

Spin Filtering

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Chemical Modification of Combusted Coal Gangue for U(VI) Adsorption: Towards a Waste Control by Waste Strategy

Sustainability ◽

10.3390/su13158421 ◽

2021 ◽

Vol 13 (15) ◽

pp. 8421

Author(s):

Yuan Gao ◽

Jiandong Huang ◽

Meng Li ◽

Zhongran Dai ◽

Rongli Jiang ◽

...

Keyword(s):

Structural Analysis ◽

High Efficiency ◽

Low Cost ◽

Chemical Activation ◽

Cost Effective ◽

Coal Gangue ◽

Order Kinetic ◽

Practical Applications ◽

Detailed Structural Analysis ◽

Alkaline Conditions

Uranium mining waste causes serious radiation-related health and environmental problems. This has encouraged efforts toward U(VI) removal with low cost and high efficiency. Typical uranium adsorbents, such as polymers, geopolymers, zeolites, and MOFs, and their associated high costs limit their practical applications. In this regard, this work found that the natural combusted coal gangue (CCG) could be a potential precursor of cheap sorbents to eliminate U(VI). The removal efficiency was modulated by chemical activation under acid and alkaline conditions, obtaining HCG (CCG activated with HCl) and KCG (CCG activated with KOH), respectively. The detailed structural analysis uncovered that those natural mineral substances, including quartz and kaolinite, were the main components in CCG and HCG. One of the key findings was that kalsilite formed in KCG under a mild synthetic condition can conspicuous enhance the affinity towards U(VI). The best equilibrium adsorption capacity with KCG was observed to be 140 mg/g under pH 6 within 120 min, following a pseudo-second-order kinetic model. To understand the improved adsorption performance, an adsorption mechanism was proposed by evaluating the pH of uranyl solutions, adsorbent dosage, as well as contact time. Combining with the structural analysis, this revealed that the uranyl adsorption process was mainly governed by chemisorption. This study gave rise to a utilization approach for CCG to obtain cost-effective adsorbents and paved a novel way towards eliminating uranium by a waste control by waste strategy.

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Interfacial antiferromagnetic coupling and high spin polarization in metallic phthalocyanines

Physical Review B ◽

10.1103/physrevb.103.024435 ◽

2021 ◽

Vol 103 (2) ◽

Author(s):

Junwei Tong ◽

Feifei Luo ◽

Liuxia Ruan ◽

Guohuai Liu ◽

Lianqun Zhou ◽

...

Keyword(s):

Spin Polarization ◽

High Spin ◽

Antiferromagnetic Coupling ◽

High Spin Polarization

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Emulsions in external electric fields

Advances in Colloid and Interface Science ◽

10.1016/j.cis.2021.102455 ◽

2021 ◽

pp. 102455

Author(s):

Johan Sjöblom ◽

Sameer Mhatre ◽

Sébastien Simon ◽

Roar Skartlien ◽

Geir Sørland

Keyword(s):

Electric Fields ◽

External Electric Fields

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Hydrogen and Halogen Bonding in Homogeneous External Electric Fields: Modulating the Bond Strengths

Chemistry - A European Journal ◽

10.1002/chem.202102284 ◽

2021 ◽

Author(s):

Li Chen ◽

Jingshuang Dang ◽

Juan Du ◽

Changwei Wang ◽

Yirong Mo

Keyword(s):

Electric Fields ◽

Halogen Bonding ◽

External Electric Fields ◽

Bond Strengths

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Theoretical prediction of the trigger linkage, cage strain, and explosive sensitivity of CL-20 in the external electric fields

Journal of Molecular Modeling ◽

10.1007/s00894-020-04634-8 ◽

2021 ◽

Vol 27 (3) ◽

Author(s):

Kang-bo Sun ◽

Shu-hai Zhang ◽

Fu-de Ren ◽

Yong-Ping Hao ◽

Shu-hong Ba

Keyword(s):

Theoretical Prediction ◽

Electric Fields ◽

External Electric Fields ◽

Explosive Sensitivity

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Cisplatin under oriented external electric fields: A deeper insight into electrochemotherapy at the molecular level

International Journal of Quantum Chemistry ◽

10.1002/qua.26578 ◽

2020 ◽

Author(s):

Li Zhang ◽

Ya‐Ling Ye ◽

Xiao‐Ling Zhang ◽

Xiang‐Hui Li ◽

Qiao‐Hong Chen ◽

...

Keyword(s):

Electric Fields ◽

Molecular Level ◽

External Electric Fields ◽

Insight Into

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Ruthenium Sensitizers and Their Applications in Dye-Sensitized Solar Cells

International Journal of Photoenergy ◽

10.1155/2012/291579 ◽

2012 ◽

Vol 2012 ◽

pp. 1-21 ◽

Cited By ~ 71

Author(s):

Yuancheng Qin ◽

Qiang Peng

Keyword(s):

Solar Cells ◽

High Efficiency ◽

Low Cost ◽

Dye Sensitized Solar Cells ◽

Ruthenium Complexes ◽

Practical Applications ◽

Photovoltaic Energy ◽

Dye Sensitized ◽

Sensitized Solar Cells ◽

Excellent Stability

Dye-sensitized solar cells (DSSCs) have attracted considerable attention in recent years due to the possibility of low-cost conversion of photovoltaic energy. The DSSCs-based ruthenium complexes as sensitizers show high efficiency and excellent stability, implying potential practical applications. This review focuses on recent advances in design and preparation of efficient ruthenium sensitizers and their applications in DSSCs, including thiocyanate ruthenium sensitizers and thiocyanate-free ruthenium sensitizers.

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