Investigation Of The Mechanical,magnetic And Optical Properties Of Al₁₄Mn₂P₁₆ Based On First Principle

Diluted magnetic semiconductors are magnetic semiconductors formed by doping transition metal elements into non-magnetic semiconductors.The diluted magnetic semiconductor has the characteristics of both semiconductor and magnetism because it hosts both the degrees of freedom of electron charge and electron spin,which makes it have great significance in the field of novel functional material.For a multi-functional devices,it is very important and challenging to find candidate material system and develop effective means of induction and regulation to make them have more excellent magnetic,optical and mechanical properties.AlP is a typical ?-? compound semiconductor.Recently,in order to obtained excellent magnetic properties,the doping transition metal elements into AlP getting lots of attention.In this work,based on the first-principle calculations,a diluted magnetic semiconductor Al₁₄Mn₂P₁₆ is formed by doping a small amount of Mn atoms into AlP,comparing with the former,excellent magnetic and optical properties has been demonstrated in Al₁₄Mn₂P₁₆.Further,the response of elastic,magnetic and optical properties of Al₁₄Mn₂P₁₆ on the applied uniaxial strain,biaxial strain and hydrostatic pressure,were systematically studied,and a series of meaningful results were obtained.The main contents and achievements are summarized as follows:1?The elastic,magnetic and optical properties of Al₁₄Mn₂P₁₆ without strain were studied.On the basis of determining the optimal doping position,it is found that Al₁₄Mn₂P₁₆ is mechanically stable and better ductility,which makes up for the weakness of AlP brittleness.Intriguingly,we found that the ground state of Al₁₄Mn₂P₁₆ is ferromagnetic,and the Curie temperature above room temperature?369 K?.The calculation results of optical properties show that Al₁₄Mn₂P₁₆ has an absorption peak located at 629 nm in the visible light range.As we know that AlP is a non-magnetic semiconductor,and there is no absorption peak in the visible light range.Thus,the results pressentd demonstrated that Mn doping can not only induce magnetism in AlP,but also make it exhibit excellent optical properties,which make Al₁₄Mn₂P₁₆ has potential application in the field of magnetic or optical devices.2?The elastic,magnetic and optical properties of Al₁₄Mn₂P₁₆ under uniaxial strain were studied.The calculation of elastic properties further shows that Al₁₄Mn₂P₁₆ is mechanically stable under uniaxial strain in the range of-10%?10%.The bulk modulus,shear modulus,Young's modulus,Poisson's ratio,anisotropy factor and ductility of Al₁₄Mn₂P₁₆ all changed to different degrees under uniaxial strain,indicating that uniaxial strain has a great regulation effect on the elastic property of Al₁₄Mn₂P₁₆.In particular,the Curie temperature of Al₁₄Mn₂P₁₆ can be increased to 412 K after compression.We also found that the absorption peak in the visible region show a shift amplitude of 124 nm under uniaxial strain.These results imply that uniaxial strain is an effective method to regulate the elastic,magnetic and optical properties of Al₁₄Mn₂P₁₆,and can expand the application range of materials.3?The elastic,magnetic and optical properties of Al₁₄Mn₂P₁₆ under uniform biaxial strain are studied.The calculation of elastic properties shows that Al₁₄Mn₂P₁₆ is mechanically stable in the strain range of-6%?10%.The elastic range when compressed of biaxial strain cannot exceed-8%based on the mechanically stability criterion.The results of magnetic and optical properties show that biaxial strain can not only increase Curie temperature of Al₁₄Mn₂P₁₆,but also change the absorption peak of Al₁₄Mn₂P₁₆ in the visible region.Obviously,biaxial strain is also an effective method to regulate the elastic,magnetic and optical properties of Al₁₄Mn₂P₁₆.4?The elastic,magnetic and optical properties of Al₁₄Mn₂P₁₆ under hydrostatic pressure were studied.The calculation of elastic properties indicated that Al₁₄Mn₂P₁₆ is mechanically stable in the hydrostatic pressure range of 0?20 GPa.The ductility of Al₁₄Mn₂P₁₆ under hydrostatic pressure is more significantly improved than that under uniaxial strain and biaxial strain,indicating that hydrostatic pressure is a powerful means to improve the ductility of Al₁₄Mn₂P₁₆.When the hydrostatic pressure reaches above 15GPa,the Curie temperature of Al₁₄Mn₂P₁₆ is lower than 38 K?much lower than room temperature?.Further,the absorption peak of Al₁₄Mn₂P₁₆ in the visible range has a large range of shift,covering the red,orange,yellow and green bands.Especially,when the hydrostatic pressure reaches 20 GPa,the absorption peak in the visible light range of Al₁₄Mn₂P₁₆ disappears suddenly.Under the regulation of hydrostatic pressure,Al₁₄Mn₂P₁₆has two important phenomena,namely,the sharp weakening of magnetism and the disappearance of absorption peak in visible light range,indicating that hydrostatic pressure has a strong regulation effect on the magnetic and optical properties of Al₁₄Mn₂P₁₆.