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Layered transition metal dichalcogenides (LTMDs) have renewed interest as electronic materials, but the poor conductivities hinder their further development. Chemical doping can often significantly modify atomic structures and electronic functionalities of a wide range of materials and thus acts as one of the most effective ways to precisely tune material properties for technological application. Here, the geometries and band structures as well as the densities of states of pure NbSe2 and Ti-doped NbSe2 nanostructure are studied by employing the ab-initio plane-wave ultra-soft pseudo potential technique based on the density functional theory. We optimize the ground state of NbSe2 in the layered structure by using the generalized gradient approximation for the exchange-correlation potential. The computational structural parameters are in good agreement with experimental values within 2.5%. To investigate the stability of the doped system with changing the concentration of Ti atoms, 2×2×1 2H-NbSe2 supercells are taken into consideration. Meanwhile, we consider a total of three possible Ti-doping models: substitution, intercalation, and embedded model, and investigate the energy band diagrams, state densities and densities of partial wave state diagram before and after the doping. The results show that the energy electron density of states reaches a higher peak, and the band structure near Fermi level (EF) is changed obviously, resulting in the variations of the band gap and EF position and then the increase of electronic conductivity after doping. In addition, our calculations also predict that the electron transport properties can be enhanced by doping Ti and it can be regarded as a useful way to tailor electronic states so as to improve electron transport properties of 2H-NbSe2. Such a remarkable modification of electronic structure of 2H-NbSe2 by chemical doping offers an additional way of modulating performances of LTMDs and developing new electrical contact composite materials.
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Keywords:
- NbSe2 /
- doping /
- electronic structure /
- first principles calculation
[1] Xiao D, Liu G B, Feng W X, Xu X D, Yao W 2012 Phys. Rev. Lett. 108 196802
[2] Song S S, Howard S, Liu Z J, Afusat O 2006 Appl. Phys. Lett. 89 041115
[3] Chang K, Chen W X 2011 J. Mater. Chem. 21 17175
[4] Xu J, Tang H, Chu Y Q, Li C S 2015 RSC. Adv. 5 48492
[5] Tenne R 1995 Adv. Mater. 7 965
[6] 津田谷裕子, 松永が长いです 1978 固体潤滑ハンドブック (Vol.1) (Beijing: Mechanical Industry Press) p268 (in Chinese) [津谷裕子, 松永正久 1978 固体润滑手册(第一版)(北京: 机械工业出版社) 第268页]
[7] Rowe G W 1960 Wear 3 274
[8] Winer W O 1967 Wear 10 422
[9] Qin X P, Ke P L, Wang A Y, Kim K H 2013 Surf. Coat. Technol. 228 275
[10] Wang Z G, Su Q L, Yin G Q, Shi J, Deng H Q, Guan J, Wu M P, Zhou Y L, Lou H L, Fu Y Q 2014 Mater. Chem. Phys. 147 1068
[11] Snure M, Kumar D, Tiwari A 2009 Appl. Phys. Lett. 94 012510
[12] Zheng S W, He M, Li S T, Zhang Y 2014 Chin. Phys. B 23 087101
[13] Wang Y Z, Xu Z P, Zhang W X, Zhang X, Wang Q, Zhang L 2014 Acta Phys. Sin. 63 237101 (in Chinese) [王永贞, 徐朝鹏, 张文秀, 张欣, 王倩,张磊 2014 63 237101]
[14] Koh Y Y, Kim Y K, Jung W S 2011 Phys. Chem. Solids 72 565
[15] Iavarone M, Karapetrov G, Fedor J 2010 Phys.: Condens. Matter. 22 015501
[16] Wu M S, Xu B, Liu G, Ouyang C Y 2013 Acta Phys. Sin. 62 037103 (in Chinese) [吴木生, 徐波, 刘刚, 欧阳楚英 2013 62 037103]
[17] Hammer B, Hansen L B, Nørskov J K 1999 Phys. Rev. B 59 7413
[18] Vanderbilt D 1990 Phys. Rev. B 41 7892
[19] Zheng S W, Fan G H, He M, Zhao L Z 2012 Acta Phys. Sin. 61 057102 (in Chinese) [郑树文, 范广涵, 何苗, 赵灵智 2012 61 057102]
[20] Sun J, Wang H T, He J 2005 Phys. Rev. B 71 125132
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[1] Xiao D, Liu G B, Feng W X, Xu X D, Yao W 2012 Phys. Rev. Lett. 108 196802
[2] Song S S, Howard S, Liu Z J, Afusat O 2006 Appl. Phys. Lett. 89 041115
[3] Chang K, Chen W X 2011 J. Mater. Chem. 21 17175
[4] Xu J, Tang H, Chu Y Q, Li C S 2015 RSC. Adv. 5 48492
[5] Tenne R 1995 Adv. Mater. 7 965
[6] 津田谷裕子, 松永が长いです 1978 固体潤滑ハンドブック (Vol.1) (Beijing: Mechanical Industry Press) p268 (in Chinese) [津谷裕子, 松永正久 1978 固体润滑手册(第一版)(北京: 机械工业出版社) 第268页]
[7] Rowe G W 1960 Wear 3 274
[8] Winer W O 1967 Wear 10 422
[9] Qin X P, Ke P L, Wang A Y, Kim K H 2013 Surf. Coat. Technol. 228 275
[10] Wang Z G, Su Q L, Yin G Q, Shi J, Deng H Q, Guan J, Wu M P, Zhou Y L, Lou H L, Fu Y Q 2014 Mater. Chem. Phys. 147 1068
[11] Snure M, Kumar D, Tiwari A 2009 Appl. Phys. Lett. 94 012510
[12] Zheng S W, He M, Li S T, Zhang Y 2014 Chin. Phys. B 23 087101
[13] Wang Y Z, Xu Z P, Zhang W X, Zhang X, Wang Q, Zhang L 2014 Acta Phys. Sin. 63 237101 (in Chinese) [王永贞, 徐朝鹏, 张文秀, 张欣, 王倩,张磊 2014 63 237101]
[14] Koh Y Y, Kim Y K, Jung W S 2011 Phys. Chem. Solids 72 565
[15] Iavarone M, Karapetrov G, Fedor J 2010 Phys.: Condens. Matter. 22 015501
[16] Wu M S, Xu B, Liu G, Ouyang C Y 2013 Acta Phys. Sin. 62 037103 (in Chinese) [吴木生, 徐波, 刘刚, 欧阳楚英 2013 62 037103]
[17] Hammer B, Hansen L B, Nørskov J K 1999 Phys. Rev. B 59 7413
[18] Vanderbilt D 1990 Phys. Rev. B 41 7892
[19] Zheng S W, Fan G H, He M, Zhao L Z 2012 Acta Phys. Sin. 61 057102 (in Chinese) [郑树文, 范广涵, 何苗, 赵灵智 2012 61 057102]
[20] Sun J, Wang H T, He J 2005 Phys. Rev. B 71 125132
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