Half-metallic ferromagnetism in hypothetical wurtzite structure chromium chalcogenides

2004 ◽  
Vol 19 (9) ◽  
pp. 2738-2741 ◽  
Author(s):  
Ming Zhang ◽  
Ekkes Brück ◽  
Frank R. de Boer ◽  
Guodong Liu ◽  
Haining Hu ◽  
...  

The hypothetical wurtzite structure chromium chalcogenides were investigated through first-principle calculation within density-functional theory. All compounds are predicted to be true half-metallic ferromagnets with an integer Bohr magneton of 4 μB per unit. Their half-metallic gaps are 1.147, 0.885, and 0.247 eV at their equilibrium volumes for wurtzite-type CrM (M = S, Se, and Te), respectively. The half-metallicity can be maintained even when volumes are expanded by more than 20% for all compounds and compressed by more than 20%, 20%, and 5%, for CrS, CrSe, and CrTe, respectively.

2012 ◽  
Vol 90 (6) ◽  
pp. 531-536 ◽  
Author(s):  
M. Moradi ◽  
M. Rostami ◽  
M. Afshari

The magnetic properties of MS (M = Li, Na, K) compounds in a Wurtzite structure at zero pressure are investigated by using first principle calculations and the pseudopotential self-consistent method based on density functional theory. It is shown that MS compounds in Wurtzite structure are half-metallic ferromagnets with a magnetic moment of μB per formula unit and half-metallic gaps of 0.24, 0.52, and 0.62 eV for LiS, NaS, and KS, respectively. We also consider the effect of pressure on the half-metallicity of these compounds and we find that LiS, NaS, and KS in Wurtzite structure maintain their half-metallicity up to lattice compressions of 9%, 37%, and 60%, respectively, and as a result one can grow them over the semiconductors in Wurtzite structures that are produced experimentally. These properties cause Wurtzite MS compounds to be appropriate choices to create useful devices in spintronics.


2020 ◽  
Vol 213 ◽  
pp. 01023
Author(s):  
Kaihao Geng ◽  
Haining Cao ◽  
Meng-Chang Lin

There is still controversy on the atomistic configuration of aluminium-ion batteries (AIB) cathode when using first principle calculation based on density functional theory (DFT). We examined the relevant cathodic structures of Al/graphite battery by employing several van der Waals (vdW) corrections. Among them, DFT-TS method was determined to be a better dispersion correction in correctly rendering structural features already found through experiment investigations. The systematic comparison paved the way to the choice of vdW parameters in first principle calculation of graphitic electrode.


2014 ◽  
Vol 556-562 ◽  
pp. 43-46
Author(s):  
Ming Zhu Yang ◽  
Mei Shan Wang

In order to lay theoretical foundations for preparation of Ga0.75Al0.25N photocathodes, research on ternary Ш-V alloys Ga0.75Al0.25N are carried on. Using CASTEP software package based on density functional theory within a plane wave ultrasoft pseudo potential scheme, total energies, band structures, density of states, and charge distribution of three different structures of wurtzite Ga0.75Al0.25N are calculated. Results show that the structure in which Al atoms in para-positon of interlayer is most stable. Ga0.75Al0.25N is semiconductor with direct band gap. The threshold wavelength is 321.8nm which can satisfy the need of preparation of “solar blind” photocathodes.


2015 ◽  
Vol 26 (01) ◽  
pp. 1550009 ◽  
Author(s):  
Fayyaz Hussain ◽  
Y. Q. Cai ◽  
M. Junaid Iqbal Khan ◽  
Muhammad Imran ◽  
Muhammad Rashid ◽  
...  

We demonstrate enhanced ferromagnetism in copper doped two-dimensional GaN monolayer ( GaN -ML). Our first principle calculation based on density functional theory predicted that nonmagnetic Cu -dopant with concentration of 6.25% to be ferromagnetic (FM) in 2D GaN layer which carries a magnetic moment of 2.0 μB per Cu atom and it is found to be long range magnetic coupling among the Cu -dopant. The Cu-dopant in 2D GaN -ML which can be explained in terms of p-d hybridization at Curie temperature and this dopant prefer the FM behavior in 2D GaN layer. Hence Cu doped 2D GaN layer shows strong magnetic properties so that it is a promising material in the field of spintronics.


2019 ◽  
Vol 9 (14) ◽  
pp. 2859 ◽  
Author(s):  
Haishen Huang ◽  
Kun Yang ◽  
Wan Zhao ◽  
Tingyan Zhou ◽  
Xiude Yang ◽  
...  

In this paper, the structure and the electronic and magnetic properties of VFeScZ (Z = Sb, As, P) series alloys are systematically studied based on the Perdew–Burke–Ernzerhof (PBE) generalized gradient approximation (GGA) calculation within the first-principles density functional theory. The results showed that VFeScSb and VFeScP are ferromagnetic semiconductors and VFeScAs exhibits half-metallic ferromagnetism under zero pressure. As the pressure increases, the narrow indirect gap of VFeScZ (Z = Sb, As, P) alloy gradually decreases, and gets close to zero, leading to spin gapless semiconductor (SGS) transition. The pressure phase transition point of VFeScSb, VFeScAs, and VFeScP alloy is 132 GPa, 58 GPa, and 32 GPa, respectively. As a result, the pressure effect provides an opportunity to tune the electronic properties of the alloys by external pressure. The present findings provide a technical method for us to actually use the Heusler alloy SGS.


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