Half Metallic Behavior in H-Terminated Zigzag BC2N Nanoribbons

2017 ◽  
Vol 864 ◽  
pp. 30-35
Author(s):  
Xiang Xiao ◽  
Hong Li ◽  
Jun Tie ◽  
Jing Lu

We study structural, stability, electronic and magnetic properties of zigzag-edged BC2N nanoribbons (ZBC2NNRs) with H-termination in the view of first principles calculations. Four kinds of edge arrangements are considered, labeled as B-C, N-C, N-B, and C-C. Interestingly, we find these four types of H-terminated ZBC2NNRs have various electronic structures. The half-metal and semi-metal are obtained depending on the edge atom alignment. The B-C and N-C ZBC2NNRs with H-termination are half-metals with antiferromagnetic (AFM) ground states. The magnetic moments of the antiferromagnetic (AFM) state always prefer to locate at the ribbon edges. However, the N-B and C-C ZBC2NNRs show spin-unpolarized semi-metallic behaviors at ground states. Our results suggest that the H-terminated ZBC2NNRs can be a promising candidate material in nanoelectronics and nanospintronics.

2016 ◽  
Vol 34 (2) ◽  
pp. 251-259 ◽  
Author(s):  
Zhi Ren ◽  
Yang Liu ◽  
Songtao Li ◽  
Xiaohong Zhang ◽  
Heyan Liu

AbstractThe electronic structure and magnetism of Mn2RhZ (Z = Al, Ga, In, Si, Ge, Sn, Sb) Heusler alloys have been studied by using first-principles calculations. Three half-metallic ferromagnets, namely, Mn2RhAl, Mn2RhGe and Mn2RhSb have been considered. The calculated equilibrium lattice constant increases with increasing atomic number of Z atoms lying in same column of periodic table. The calculated total magnetic moments Mtot are 2 µB/f.u. for Mn2RhAl and Mn2RhGa, 3 µB/f.u. for Mn2RhSi, Mn2RhGe and Mn2RhSn, and 4 µB/f.u. for Mn2RhSb, which agrees with the Slater-Pauling curve quite well. In all these compounds, except for Mn2RhSb, the moments of Mn (A) and Mn (B) are antiparallel to each other. The total magnetic moments of the three considered half-metals assume integral values in a wide range of equilibrium lattice parameters.


2017 ◽  
Vol 31 (14) ◽  
pp. 1750109 ◽  
Author(s):  
Heidar Khosravi ◽  
Arash Boochani ◽  
Golnaz Rasolian ◽  
Shahram Solaymani ◽  
Sirvan Naderi

First-principles study of elastic, electronic and optical properties of full-Heusler Co2V(Al, Ge, Ga and Si) compounds are calculated through density functional theory (DFT) to obtain and compare the mentioned properties. Equilibrium lattice constants of these compounds are in good agreement with other works. Electronic calculations are shown full spin polarization at Fermi level for all compounds, so in the down spin, indirect bandgap is calculated as 0.33, 0.6, 0.2 and 0.8 eV for Co2V(Al, Ge, Ga and Si), respectively. The integer amounts of the magnetic moments are compatible with Slater–Pauling role. The optical treatment of Co2VGa is different from three other compounds. All mentioned compounds have metallic behavior by 22 eV plasmonic frequency. The imaginary part of the dielectric function for the up spin indicates that the main optical transitions occurred in this spin mode. Moreover, the elastic results show that the Co2VGa does not have elastic stability, but the other three compounds have fully elastic stability and the Co2V(Al, Ge and Si) belong to the hardness of materials.


Author(s):  
KAI LI ◽  
ANNA SHIN HWA LEE ◽  
YONG-WEI ZHANG ◽  
HUI PAN

In this paper, first-principles calculations are carried out to study the electronic and magnetic properties of silicene and silicane nanoribbons, with and without H -passivation at the edges. We predict that the armchair nanoribbons are nonmagnetic and semiconducting. Interestingly, the band gaps of armchair silicene nanoribbons show oscillating behavior as the ribbon width increases. When their edges are passivated with H atoms, However, the oscillating phase is reversed. The zigzag nanoribbons are anti-ferromagnetic and semiconducting in their ground states, except that the zigzag silicane nanoribbons with edges passivated by H atoms are nonmagnetic. The zigzag silicane nanoribbons with bare edges show the highest magnetic moments in their ground states. The band gaps of zigzag nanoribbons in their ground states decrease with the increment of width. The metastable states of zigzag silicene nanoribbons are ferromagnetic and metallic. The zigzag silicane nanoribbons with bare edges are ferromagnetic and semiconducting in their metastable states. The silicene/silicane nanoribbons with attractive functions, which are achievable by edge engineering or external fields, may be applied to spintronic technologies and nanodevices.


2010 ◽  
Vol 24 (14) ◽  
pp. 2229-2235
Author(s):  
KAIHUA HE ◽  
GUANG ZHENG ◽  
HANLIE HONG ◽  
MIAO WAN ◽  
GUANGFU JI

The electronic structure and ferromagnetism of Sn 2 Co 2 O 8 and Sn 2 Co 2 O 7 have been investigated based on the first-principles plane-wave pseudopotential method within the generalized gradient approximation. The calculated results reveal that the oxygen vacancy plays an important role in the electronic structure and ferromagnetism. The Sn 2 Co 2 O 8 shows half-metallic behavior, but by introducing single oxygen vacancy, the half-metallic transits to metallic behavior. At the same time, the spin magnetic moment of every Co atom and the total magnetic moment change greatly. For Sn 2 Co 2 O 8 and Sn 2 Co 2 O 7, the total spin magnetic moments are 1.99 and 3.49 uB, respectively.


2020 ◽  
Vol 62 (1) ◽  
pp. 1-14
Author(s):  
A. Maafa ◽  
H. Rozale ◽  
A. Oughilas ◽  
A. Boubaça ◽  
A. Amar ◽  
...  

AbstractIn the purpose of exploring new Heusler alloys with different magnetic applications, we have employed first principles calculations method within density functional theory. After checking the structural stability of X2YZ Heusler alloys (X = Fe, Co; Y =Zr, Mo and Z = Ge, Sb), we found that Cu2MnAl type structure is more favorable for most compounds except for X2MoGe and Co2MoSb, were the Hg2CuTi structure is energetically more stable. The trends in magnetic and electronic structures can be predicted by the structure types as well as the different kinds of hybridizations between the constituents. Among the two series only two compounds were identified to be true half metals with potential applications in spintronic devices. While one compound was classified as a nonmagnetic semiconductor with a small band gap. For the rest of materials, we found that the metallic behavior is dominant. These materials show possible interesting features in technical applications as well. The effect of distortion on the magnetic properties of Co2ZrGe and Fe2ZrSb showed that the half metallic character was preserved within a moderate range of volume changes, which makes it possible to grow these materials as thin films with modern techniques.


2011 ◽  
Vol 25 (18) ◽  
pp. 1537-1548 ◽  
Author(s):  
M. YOGESWARI ◽  
G. KALAPANA

Self-consistent ab initio calculations were carried out to study the structural, electronic and magnetic properties of nine ternary compounds Ca 4 XA 3 ( X = B , C and N ; A = S , Se and Te ). The calculations were performed by using tight-binding linear muffin tin orbital (TB-LMTO) method within the local density approximation (LDA). The calculations reveal that half-metallic ferromagnetism can be obtained for C - and N -doping with the integer magnetic moment of 2.00 μ B and 1.00 μ B per cell. However, B substitution does not induce magnetism in CaS and CaSe systems, but it produces ferromagnetism in CaTe system with magnetic moment of 2.67 μ B per cell. Moreover C - and N -doping enhance the stable ferromagnetic state in calcium chalcogenide systems. Spin-dependent electronic band structure, total and partial densities of state calculations demonstrate that localized magnetic moments substantially come from impurity atoms. Half-metallic ferromagnetism predominately originates from spin-polarization of electrons in 2p orbital states of C and N atoms. In addition, equilibrium lattice constant, bulk modulus, atomic local magnetic moments, half-metallic gap and robustness of half-metallicity have been calculated.


2020 ◽  
Vol 98 (3) ◽  
pp. 291-296 ◽  
Author(s):  
Shabbir Ahmed ◽  
M. Shakil ◽  
Muhammad Zafar ◽  
M.A. Choudhary ◽  
T. Iqbal

We have studied the structural, electronic, and magnetic properties of CrMnX (X = Ge, Se, Si, and Sn) compounds. The first principles band structure calculation within the framework of density functional theory was used to explore these properties. The full-potential linearized augmented plane wave (FP-LAPW) method as implemented in the Wien2k software package has been used. We investigated the effect of compositional variation on lattice constants, bulk modulus, electronic, and magnetic properties. CrMnSi has the largest while CrMnSe has the smallest bulk modulus among the studied compounds. Our calculated electronic and magnetic properties for CrMnX (X = Ge, Se, Si, and Sn) compounds show that CrMnGe, CrMnSe, and CrMnSi are half-metallic materials with integer magnetic moments while CrMnSn has metallic behavior. These compounds are fascinating for spintronic devices due to their half-metallic properties.


2021 ◽  
Vol 3 ◽  
pp. e15
Author(s):  
Amall Ahmed Ramanathan ◽  
Jamil Mahmoud Khalifeh

The density functional theory (DFT) full potential linearized augmented plane wave (FP-LAPW) method with the modified Becke–Johnson (mBJ) approximation is used to perform spin polarised calculations of the transition metal perovskites MoScO3 and WScO3. Both depict half metallic behaviour with semiconducting and metallic in the minority and majority spins respectively. MoScO3 and WScO3 have indirect R− Γ band gaps in the minority spin channels of 3.61 and 3.82 eV respectively. Moreover, they both show substantial integer magnetic moments of 3μB with 100% spin polarization typical to half metals. In addition, we calculate the dielectric function, optical conductivity and the optical constants, namely, the refractive index, the reflectivity, the extinction and absorption coefficients.


Materials ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 3501
Author(s):  
Shengqiang Lai ◽  
Yongping Du

The electronic structure, magnetic properties and strain response of N-a-TiS3 nanoribbons are investigated by first-principles calculations. We find that the magnetic ground state is strongly dependent on width of a-TiS3. When N equals an odd number the ground state is a ferromagnetic (FM) metal, meanwhile, when N equals an even number the ground state is an anti-ferromagnetic (AFM) metal. More interestingly, a tensile strain as large as 6% can tune the 9-a-TiS3 nanoribbon from a FM metal to a half metal. A 4% tensile strain also causes a phase transition from AFM to FM ground state for 10-a-TiS3 nanoribbon. Our findings show that N-a-TiS3 is a promising candidate for spintronic and electronic applications.


2011 ◽  
Vol 415-417 ◽  
pp. 1407-1410
Author(s):  
Qing Zhou ◽  
Bo Wu ◽  
Hong Kuan Yuan ◽  
Hong Chen

By using the first-principles calculations within the density functional theory (DFT), we investigate the electronic structure, magnetism and half-metallic stability of half-Heusler compound NiMn1-xNbxSb. The results showed that the lattice constants and magnetic moments per unit respectively follow the Vegard law and the Slater-Pauling rule well. The most stable half-metallicity occurs at doping concentration x=0.25 due to the Fermi level is situated the middle of the spin-down gap. Our studies also indicate that the competition of hybridization of d-electrons and RKKY-type magnetic coupling plays a dominating role in determining the magnetism.


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