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Manipulation of Magnetic State in Armchair Black Phosphorene Nanoribbon by Charge Doping
Farooq, M. Umar,Hashmi, Arqum,Hong, Jisang American Chemical Society 2015 ACS APPLIED MATERIALS & INTERFACES Vol.7 No.26
<P>Using first-principles studies, we investigated the width-dependent magnetic properties of armchair black phosphorene nanoribbons (APNRs) by controlling the electron charge doping. In the unrelaxed APNRs the antiferromagnetic coupling between two phosphorus atoms in the same edge was found. However, the edge magnetic moment vanished after structure relaxation, and all of the APNRs showed a semiconducting feature. Interestingly, the charge doping substantially altered the band structures of the APNRs because the metallic states reappeared in the charge-doped APNRs. Besides this, the magnetic moment was found in the charge-doped systems. We found that the Stoner condition could nicely explain the magnetic moment at the edge atoms. Moreover, we propose that the edge-to-edge magnetic coupling can be manipulated by charge doping because the transition from the antiferromagnetic to ferromagnetic state was achieved. Our findings may bring interesting issues for spintronics applications.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2015/aamick.2015.7.issue-26/acsami.5b03284/production/images/medium/am-2015-03284j_0008.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am5b03284'>ACS Electronic Supporting Info</A></P>
A Centralized e-pedigree system for Agriculture Food Distribution Network
Umar Farooq,Ganjar Alfian,M. Alex Syaekhoni,HyeJung Ahn,Jongtae Rhee 한국경영과학회 2014 한국경영과학회 학술대회논문집 Vol.2014 No.5
Food quality and safety has attained the considerable attention, because of the consumers increasing health awareness, improved economic standards and lifestyle of modern societies. Thus, it is important for distributors, retailers and consumers to purchase agriculture food products and track that they have come through the legal and safe distribution channels. In this paper we proposed a Centralized EPCIS and Sensor Data Repositories based e-pedigree system for agriculture food products to guarantee the quality, safety and reliability of agriculture food products for final consumers. This system not only assure the authenticity of the agriculture food products but also assure the food quality through environmental information such as temperature and humidity during storage, distribution and transportation for food quality.
A Centralized e-pedigree system for Agriculture Food Distribution Network
Umar Farooq,Ganjar Alfian,M. Alex Syaekhoni,HyeJung Ahn,Jongtae Rhee 대한산업공학회 2014 대한산업공학회 춘계학술대회논문집 Vol.2014 No.5
Food quality and safety has attained the considerable attention, because of the consumers increasing health awareness, improved economic standards and lifestyle of modern societies. Thus, it is important for distributors, retailers and consumers to purchase agriculture food products and track that they have come through the legal and safe distribution channels. In this paper we proposed a Centralized EPCIS and Sensor Data Repositories based e-pedigree system for agriculture food products to guarantee the quality, safety and reliability of agriculture food products for final consumers. This system not only assure the authenticity of the agriculture food products but also assure the food quality through environmental information such as temperature and humidity during storage, distribution and transportation for food quality.
Hashmi, Arqum,Farooq, M. Umar,Hu, Tao,Hong, Jisang American Chemical Society 2015 The Journal of Physical Chemistry Part C Vol.119 No.4
<P>Half-metallic materials play an essential role in the spin-dependent transport study, and so far it is believed that the 3d transitional metal elements are necessary to obtain a ferromagnetic state. Herein, we demonstrate that the metal free two-dimensional graphitic carbon nitride (g-C<SUB>4</SUB>N<SUB>3</SUB>) film show half metallic state and this is independent of the film thickness and stacking order. We find that the half-metallicity results in a very large magnetoresistance even at finite bias. Moreover, we have also investigated various optical properties. The g-C<SUB>4</SUB>N<SUB>3</SUB> thin films have a very high refractive index for parallel polarization and extremely weak reflectivity for perpendicular polarization. Additionally, the g-C<SUB>4</SUB>N<SUB>3</SUB> thin films are optically transparent because of very weak absorption coefficients. Overall, our findings suggest that the transparent half-metallic g-C<SUB>4</SUB>N<SUB>3</SUB> thin films can be used for both spintronics and optical applications because of potential multifunctionality.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/jpccck/2015/jpccck.2015.119.issue-4/jp510179p/production/images/medium/jp-2014-10179p_0007.gif'></P>
Two-dimensional honeycomb hafnene monolayer: stability and magnetism by structural transition
Hashmi, Arqum,Umar Farooq, M.,Khan, Imran,Hong, Jisang Royal Society of Chemistry 2017 Nanoscale Vol.9 No.28
<P>A few years ago, it was claimed that the two-dimensional ferromagnetic planar Hf monolayer could be synthesized on Ir(111). However, several questions remained unanswered. Herein, we unravel the structural stability of the HF monolayer and its influence on magnetism using first principles calculations. Despite the ferromagnetic state in the planar free-standing Hf layer, extensive systematic calculations with phonon spectra reveal that the planar free-standing Hf layer is unstable and it has a non-magnetic high-buckled structure in the ground state. We also find a structural transition from buckled to flat honeycomb geometry on the Ir(111) substrate. Nonetheless, 2D hafnene has no magnetic state due to strong hybridization with the Ir(111) surface. The evolution from the non-magnetic to the ferromagnetic state combined with structural transition is observed by adding BN as a spacer layer on the Ir(111) substrate (BN/Ir(111)). In addition, we find that 2D Hf on BN/Ir(111) has a giant perpendicular magnetic anisotropy of 3.41 meV.</P>
Two-Dimensional Magnetic Semiconductor in Feroxyhyte
Khan, Imran,Hashmi, Arqum,Farooq, M. Umar,Hong, Jisang American Chemical Society 2017 ACS APPLIED MATERIALS & INTERFACES Vol.9 No.40
<P>A few years ago, it was claimed that the two-dimensional (2D) feroxyhyte (delta-FeOOH) layer could possess a net magnetic moment and it could be applied for potential spintronics applications because it showed a band gap. However, the exact crystal structure is still unknown. Hereby, we investigate the crystal structure, electronic band structure, and magnetic and optical properties of 2D delta-FeOOH using density functional calculations. On the basis of the experimental observation and dynamical stability calculations, we propose that the 2D delta-FeOOH originates from bulk Fe(OH)(2) via oxidation. A perfect antiferromagnetic ground state was observed in the monolayer structure with an indirect band gap of 2.4 eV. On the other hand, the bilayer structure displayed a direct band gap of 0.87 eV, and we obtained a ferrimagnetic state. The net magnetic moment in the bilayer was 1.49 mu(B) per cell. The interlayer distance and film thickness in bilayer delta-FeOOH were 1.68 and 7.37 angstrom, respectively. This interlayer distance was suppressed to 1.47 angstrom in a trilayer system, and the band gap of 1.6 eV was found. The trilayer delta-FeOOH had a film thickness of 11.57 angstrom, and this is comparable to the experimental thickness of 12 angstrom. To compare with the experimental band gap of 2.2 eV obtained from a UV-visible optical spectrum measurement, we also calculated the absorption spectra, and the onset of the absorption peak in the monolayer, bilayer, and trilayer appeared at 3.2, 2.8, and 2.2 eV, respectively. Overall, considering the magnetic state, optical absorption, and film thickness, we propose that the trilayer structure agrees with the experimentally synthesized structure.</P>