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| 1 | Theoretical investigations of half-metallic ferromagnetism in new Half-Heusler YCrSb and YMnSb alloys using first-principle calculations显示文摘Structural,electronic,and magnetic properties of new predicted half-Heusler YCrSb and YMnSb compounds within the ordered MgAgAs Clb-type structure are investigated by employing first-principal calculations based on density functional theory.Through the calculated total energies of three possible atomic placements,we find the most stable structures regarding YCrSb and YMnSb materials,where Y,Cr(Mn),and Sb atoms occupy the(0.5,0.5,0.5),(0.25,0.25,0.25),and(0,0,0) positions,respectively.Furthermore,structural properties are explored for the non-magnetic and ferromagnetic and anti-ferromagnetic states and it is found that both materials prefer ferromagnetic states.The electronic band structure shows that YCrSb has a direct band gap of 0.78 eV while YMnSb has an indirect band gap of 0.40 eV in the majority spin channel.Our findings show that YCrSb and YMnSb materials exhibit half-metallic characteristics at their optimized lattice constants of 6.67 and 6.56 ,respectively.The half-metallicities associated with YCrSb and YMnSb are found to be robust under large in-plane strains which make them potential contenders for spintronic applications. | M Atif Sattar Muhammad Rashid M Raza Hashmi S A Ahmad Muhammad Imran Fayyaz Hussain | 2016 | Chinese Physics B2016，25，10： | 1 |
| 2 | First-principles prediction of magnetically ordered half-metals above room temperature显示文摘Half-metallicity(HM)offers great potential for engineering spintronic applications,yet only few magnetic materials present metallicity in just one spin channel.In addition,most HM systems become magnetically disordered at temperatures well below ambient conditions,which further hinders the development of spin-based electronic devices.Here,we use first-principles methods based on density functional theory(DFT)to investigate the electronic,magnetic,structural,mixing,and vibrational properties of 90 XYZ half-Heusler(HH)alloys(X=Li,Na,K,Rb,Cs;Y=V,Nb,Ta;Z=Si,Ge,Sn,S,Se,Te).We disclose a total of 28 new HH compounds that are ferromagnetic,vibrationally stable,and HM,with semiconductor band gaps in the range of 1-4 eV and HM band gaps of 0.2-0.8 eV.By performing Monte Carlo simulations of a spin Heisenberg model fitted to DFT energies,we estimate the Curie temperature,T_(C),of each HM compound.We find that 17 HH HM remain magnetically ordered at and above room temperature,namely,300≤T_(C)≤450 K,with total magnetic moments of 2 and 4 mB.A further materials sieve based on zero-temperature mixing energies let us to conclude 5 overall promising HH HM that remain magnetically ordered at and above room temperature:NaVSi,RbVTe,CsVS,CsVSe,and RbNbTe.We also predict 2 semiconductor materials that are ferromagnetic at ambient conditions:LiVSi and LiVGe. | Muhammad Atif Sattar S.Aftab Ahmad Fayyaz Hussain Claudio Cazorla | 2019 | Journal of Materiomics2019，5，3： | 0 |
| 3 | Directional mechanical and thermal properties of single-layer black phosphorus by classical molecular dynamics显示文摘Black phosphorus(BP) has received attention due to its own higher carrier mobility and layer dependent electronic properties, such as direct band gap. Interestingly, the single layer black phosphorus(SLBP) has had large popularity in applications related to thermoelectric, optoelectronic, and electronic devices. Here, we investigate the phonon spectrum,thermal conductivities, and stress strain effects. Robust anisotropy was mainly observed in the thermal conductivities together with the alongside zigzag(ZZ) direction value, compared to the armchair(AC) directions. We also investigated the attitude of stress that was anisotropic in both directions, and the stress effects were two times greater across the ZZ path than those in the AC direction at a low temperature. We obtained a Young's modulus of 63.77 and 20.74 GPa in the AC and ZZ directions, respectively, for a strain range of 0.01. These results had good agreement with first principle calculations.Our study here is useful and significant for the thermal tuning of phosphorus-based nanoelectronics and thermalelectric applications of phosphorus. | Afira Maryam Ghulam Abbas Muhammad Rashid Atif Sattar | 2018 | Chinese Physics B2018，27，1： | 0 |
| 4 | Ab-initio investigation of AGeO_3(A=Ca, Sr) compounds via Tran Blaha-modified Becke Johnson exchange potential显示文摘We employ ab-initio calculations to analyze the mechanical, electronic, optical and also thermoelectric properties associated with AGeO_3(A = Ca, Sr) compounds. The full-potential linearized augmented plane wave(FP-LAPW) technique in the generalized gradient approximation(GGA-PBEsol) and the lately designed Tran-Blaha-modified Becke-Johnson exchange potential are utilized to examine the mechanical and optoelectronic properties respectively. To explore the thermoelectric quality, we use the semi-classical Boltzmann transport theory. The particular structural stabilities regarding AGeO3_(A = Ca, Sr) materials are validated simply by computations from the elastic constants. The energy band structural framework and the density of states are displayed to indicate indirect bandgap under ambient conditions. The particular computed optical attributes that reveal prospective optoelectronic applications are usually elucidated simply by studying ε_1(0) and also E_g, which can be connected by means of Penn's design. The optical details uncover the actual suitability to power ranging products. Finally, the Boltz Tra P code is executed to analyze the actual thermoelectric properties, which usually presents that the increase of internal temperatures can enhance the electric conductivity, thermal conductivity and also the power factor, whilst Seebeck coefficient decreases. Therefore, the studied materials will also be ideal for thermoelectric products to understand helpful option for alternative energy resources. | Rasul Bakhsh Behram M A Iqbal Muhammad Rashid M Atif Sattar Asif Mahmood Shahid M Ramay | 2017 | Chinese Physics B2017，26，11： | 0 |
| 5 | First-principles calculation of the structural,electronic,and magnetic properties of cubic perovskite RbXF3(X = Mn,V,Co,Fe)显示文摘First-principles calculations by means of the full-potential linearized augmented plane wave method using the generalized gradient approximation with correlation effect correction(GGA+U) within the framework of spin polarized density functional theory(DFT+U) are used to study the structural,electronic,and magnetic properties of cubic perovskite compounds RbXF_3(X = Mn,V,Co,and Fe).It is found that the calculated structural parameters,i.e.,lattice constant,bulk modulus,and its pressure derivative are in good agreement with the previous results.Our results reveal that the strong spin polarization of the 3d states of the X atoms is the origin of ferromagnetism in RbXF_3.Cohesive energies and the magnetic moments of RbXF_3 have also been calculated.The calculated electronic properties show the half-metallic nature of RbCoF_3 and RbFeF_3,making these materials suitable for spintronic applications. | Muhammad Raza ur rehman Hashmi Muhammad Zafar M Shakil Atif Sattar Shabbir Ahmed S A Ahmad | 2016 | Chinese Physics B2016，25，11： | 0 |
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