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二维材料由于具有独特的电子结构和量子效应、丰富的可调控特性而受到凝聚态物理和材料科学的广泛关注, 其中通过过渡金属掺杂二维WS2形成的半金属铁磁性材料在自旋电子学领域中发挥着重要的作用 . 采用基于密度泛函理论的第一性原理赝势平面波方法计算了过渡金属原子X (X = Mn, Tc, Re) 掺杂二维WS2的电子结构、磁性和光学性质. 研究表明: 被过渡金属原子X掺杂的WS2体系在S-rich条件下比在W-rich条件下更稳定. 在 Mn掺杂后, 自旋向上通道中出现杂质能级, 导致WS2体系从自旋向上和自旋向下态密度完全对称的非磁性半导体转变为磁矩1.001
$ {\text{μ}}_{\text{B}} $ 的铁磁性半金属. 在Tc, Re掺杂后, 体系均转变为非磁性N型半导体. 所有掺杂体系杂质态均发生自旋劈裂现象, 且自旋劈裂程度逐渐减小. 同时发现 Mn, Tc, Re掺杂后, 表现出优异的光学性质, 它们的介电常数和折射系数与未掺杂WS2的体系相比明显增强, 吸收系数在低能量区域 (0—2.0 eV) 均出现红移现象.Spintronics is a particularly hot topic in recent years, which has aroused much attention. The spin freedom of electrons can be used to construct logic devices and memory devices. Generally, the most important spintronic properties are found in half-metal ferromagnets, which are considered as the ideal materials for building spintronic devices due to their ability to provide fully spin-polarised conduction electrons. Numerous experimental data and theoretical studies have confirmed that the intercalation, doping and adsorption of transition metal atoms can induce magnetic properties in two-dimensional WS2 material. Therefore, half-metal ferromagnets formed by doping WS2 play an important role in the field of spintronics. In this paper, we investigate the electronic structure, magnetic and optical properties of the WS2 doped with transition metal atoms X (X = Mn, Tc, Re) by the first-principles plane wave method based on density functional theory. The results show that the WS2 system doped with transition metal atoms X is more stable under S-rich condition than under W-rich condition. Especially, the WS2 system doped with Tc has a minimum value of formation energy of –1.292 eV under S-rich condition. After doping with Mn, impurity levels appear in the spin-up channels, resulting in the WS2 system changing from a non-magnetic semiconductor to half-metal ferromagnet with a magnetic moment of 1.001$ {\text{μ}}_{\text{B}} $ . Moreover, in the Mn-doped system, the densities of states are asymmetric in the spin-up channel and the spin-down channel. After being doped with Tc and Re, the systems are transformed into non-magnetic N-type semiconductors, and the densities of states in spin-up and spin-down channels are symmetric in Tc doping system and Re doping system. Whereafter, the spin orbit splitting of the impurity states near the Fermi level EF decreases successively from Mn to Re doped WS2 systems. Compared with the undoped two-dimensional WS2, the transition metal atoms X doped WS2 systems show that all doped systems not only have a significant red shift of optical absorption edges but also enhance peak value in infrared and visible light region, implying that the transition metal atoms X doped WS2 systems have great application prospects in infrared and visible light detection. We hope that thepresent study of two-dimensional WS2 will provide useful theoretical guidance for future experiments to explore low-dimensional spintronic materials.-
Keywords:
- two-dimensional WS2 materials /
- magnetic properties /
- electronic structure /
- optical properties
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[2] De Groot R, Mueller F, van Engen P, Buschow K 1983 Phys. Rev. Lett. 50 2024Google Scholar
[3] 何聪丽, 许洪军, 汤建, 王潇, 魏晋武, 申世鹏, 陈庆强, 邵启明, 于国强, 张广宇, 王守国 2021 物理学报 70 127501Google Scholar
He C L, Xu H J, Tang J, Wang X, Wei J W, Shen S P, Chen Q Q, Shao Q M, Yu G Q, Zhang G Y Wang S G 2021 Acta Phys. Sin. 70 127501Google Scholar
[4] 俞洋, 张文杰, 赵婉莹, 林贤, 金钻明, 刘伟民, 马国宏 2019 物理学报 68 017201Google Scholar
Yu Y, Zhang W J, Zhao W Y, Lin X, Jin Z M, Liu W M, Ma G H 2019 Acta Phys. Sin. 68 017201Google Scholar
[5] Tiwari S K, Sahoo S, Wang N, Huczko A 2020 J. Sci.: Adv. Mater. Dev. 5 10Google Scholar
[6] Shen C, Ying J, Liu L, Liu J, Li N, Wang S, Tang J, Zhao Y, Chu Y, Watanabe K 2021 Chin. Phys. Lett. 38 047301Google Scholar
[7] Du J, Lyu B, Shan W, Chen J, Zhou X, Xie J, Deng A, Hu C, Liang Q, Xie G 2021 Chin. Phys. Lett. 38 056301Google Scholar
[8] Zhang X, Pan G, Zhang Y, Kang J, Meng Z Y 2021 Chin. Phys. Lett. 38 077305Google Scholar
[9] Fu Q, Han J, Wang X, Xu P, Yao T, Zhong J, Zhong W, Liu S, Gao T, Zhang Z 2021 Adv. Mater. 33 1907818Google Scholar
[10] Liu Y, Gao Y, Zhang S, He J, Yu J, Liu Z 2019 J. Nano Res. 12 2695Google Scholar
[11] Hu Z, Wu Z, Han C, He J, Ni Z, Chen W 2018 Chem. Soc. Rev. 47 3100Google Scholar
[12] Luan Q, Yang C L, Wang M S, Ma X G 2017 Chin. J. Phys. 55 1930Google Scholar
[13] Chen Y, Chen Y, Ning J, Chen L, Zhuang W, He L, Zhang R, Xu Y, Wang X 2020 Chin. Phys. Lett. 37 017104Google Scholar
[14] Zhao Y, Liu B, Yang J, He J, Jiang J 2020 Chin. Phys. Lett. 37 088501Google Scholar
[15] Zhang M L, Zou X M, Liu X Q 2020 Chin. Phys. Lett. 37 118501Google Scholar
[16] Zhou S H, Zhou C W, Yang X D, Li Y, Zhong J Q, Mao H Y 2021 Chin. Phys. Lett. 38 057305Google Scholar
[17] Wang Z, Qiu J J, Wang X, Zhang Z, Chen Y, Huang X, Huang W 2018 Chem. Soc. Rev. 47 6128Google Scholar
[18] 周倩玉, 李鑫, 刘灏, 戴三瑜, 王世锋 2021 电子元件与材料 40 10Google Scholar
Zhou Q Y, Li X, Liu H, Dai S Y, Wang S F 2021 Electr. Comp. Mater 40 10Google Scholar
[19] Rapoport L, Leshchinsky V, Lapsker I, Volovik Y, Nepomnyashchy O, Lvovsky M, Popovitz-Biro R, Feldman Y, Tenne R 2003 wear 255 785Google Scholar
[20] Farkous M, Bikerouin M, Thuan D V, Benhouria Y, El-Yadri M, Feddi E, Erguig H, Dujardin F, Nguyen C V, Hieu N V 2020 Physica E 116 113799Google Scholar
[21] 令维军, 夏涛, 董忠, 刘勍, 路飞平, 王勇刚 2017 物理学报 66 114207Google Scholar
Lin W J, Xia T, Dong Z, Liu Q, Lu F P, Wang Y G 2017 Acta Phys. Sin. 66 114207Google Scholar
[22] Sun S, Dang J, Xie X, Yu Y, Yang L, Xiao S, Wu S, Peng K, Song F, Wang Y 2020 Chin. Phys. Lett. 37 087801Google Scholar
[23] Zhang D, Cao Y, Yang Z, Wu J 2020 ACS Appl. Mater. Interfaces 12 11979Google Scholar
[24] Zhou Q, Duan J, Yang X, Duan Y, Tang Q 2020 Angew. Chem. 132 22181Google Scholar
[25] Kang K, Fu S, Shayan K, Anthony Y, Dadras S, Yuzan X, Kazunori F, Terrones M, Zhang W, Strauf S 2020 Nanotechnol. 32 095708Google Scholar
[26] Xiao S L, Yu W Z, Gao S P 2016 Surf. Sci. 653 107Google Scholar
[27] Xie L Y, Zhang J M 2017 Superlattice Microst. 112 224Google Scholar
[28] Wang M M, Zhang J M, Ali A, Wei X M, Huang Y H 2021 Physica E Low Dimens. Syst. Nanostruct. 134 114917Google Scholar
[29] Urbanová V, Lazar P, Antonatos N, Sofer Z k, Otyepka M, Pumera M 2020 ACS Appl. Mater. Interfaces 12 20383Google Scholar
[30] Singh N, Schwingenschlögl U 2016 ACS Appl. Mater. Interfaces 8 23886Google Scholar
[31] Hafner J 2008 J. Comput. Chem 29 2044Google Scholar
[32] Gross E K, Dreizler R M 2013 Density Functional Theory (Vol. 337) (Springer Science & Business Media)
[33] Bishal G 2019 Comput. Condens. Matter 18 e00352Google Scholar
[34] Zhu Y Y, Zhang J M 2018 Superlattice Microst. 117 155Google Scholar
[35] Gillan M 1989 J. Phys. Condens. Matter 1 689Google Scholar
[36] Dolui K, Rungger I, Pemmaraju C D, Sanvito S 2013 Phys. Rev. B 88 075420Google Scholar
[37] Yang Y, Feng Z Y, Zhang J M 2019 J. Magn. Magn. Mater. 486 165255Google Scholar
[38] Zhu Y Y, Zhang J M 2017 Superlattice Microst. 112 619Google Scholar
[39] Manchon A, Koo H C, Nitta J, Frolov S, Duine R 2015 Nat. Mater. 14 871Google Scholar
[40] Yang G, Gao S P 2021 Nanoscale 13 17057Google Scholar
[41] Qiu B, Zhao X, Hu G, Yue W, Yuan X, Ren J 2020 Physica E Low Dimens. Syst. Nanostruct. 116 113729Google Scholar
[42] Shu H 2020 Mater. Sci. Eng. B 261 114672Google Scholar
[43] Cong C, Shang J, Wang Y, Yu T 2018 Adv. Opt. Mater. 6 1700767Google Scholar
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图 2 能带结构(红色表示上自旋电子能带, 蓝色表示下自旋电子能带, 绿色水平虚线代表EF为零值) (a) 二维WS2; (b) Mn掺杂; (c) Tc掺杂; (d) Re掺杂
Fig. 2. Energy band structures (The red lines indicate spin-up electron energy band, the blue lines indicate spin-down electron energy band, the green horizontal dashed lines represent zero value of Fermi energy level EF): (a) Two-dimensional WS2; (b) Mn doped; (c) Tc doped; (d) Re doped.
图 4 未掺杂与掺杂二维WS2的光学性质 (a) 介电函数实部
$ {\varepsilon }_{\text{1}}\text{(}\omega \text{)} $ ; (b) 介电函数虚部$ {\varepsilon }_{\text{2}}\text{(}\omega \text{)} $ ; (c) 折射系数$ n\text{(}\omega \text{)} $ ; (d) 吸收系数$ \alpha \text{(}\omega \text{)} $ Fig. 4. Optical properties of undoped and doped two-dimensional WS2: (a) The real part of the dielectric constant
$ {\text{}\varepsilon }_{\text{1}}\text{(}\omega \text{)} $ ; (b) the imaginary part of the dielectric constant$ {\varepsilon }_{\text{2}}\text{(}\omega \text{)} $ ; (c) the refractive index$ n\text{(}\omega \text{)} $ ; (d) absorption coefficient$ \alpha \text{(}\omega \text{)} $ .表 1 未掺杂、掺杂二维WS2的体系优化后的晶格常数a (a = b) 、键长dX-S 、键角θS-X-S 以及体系在S-rich和W-rich条件下的形成能Eform
Table 1. Optimized lattice constants a (a = b), bond lengths dX-S , bond angles θS-X-S , and formation energies Eform of the system under S-rich and W-rich conditions for the undoped and doped two-dimensional WS2 systems.
体系类型 a = b/Å dX-S/Å θS-X-S/(°) Eform/eV S-rich W-rich 未掺杂 3.182 2.416(dw-s) 82.351(θS-W-S) — — Mn掺杂 3.173 2.319 82.445 –0.662 1.810 Tc掺杂 3.187 2.398 82.879 –1.292 1.180 Re掺杂 3.191 2.399 82.916 –0.668 1.804 表 2 未掺杂与掺杂二维WS2体系的总磁矩Mtot、TM原子X的局部磁矩MX、与TM原子X最近邻S原子的局部磁矩MS以及与TM原子X最邻近W原子的局部磁矩MW
Table 2. Total magnetic moments Mtot, the local magnetic moments MX of TM atom X, the local magnetic moments MS of nearest S atom to TM atom X and the local magnetic moments MW of nearest W atom to TM atom X for undoped and doped two-dimensional WS2 systems.
体系类型 Mtot/$ {\text{μ}}_{\text{B}} $ MX/$ {\text{μ}}_{\text{B}} $ MS/$ {\text{μ}}_{\text{B}} $ MW/$ {\text{μ}}_{\text{B}} $ 未掺杂 — — — — Mn掺杂 1.001 1.087 0.006 0.010 Tc掺杂 — — — — Re掺杂 — — — — 表 3 自旋向上通道的带隙
$ {E}_{\text{g}}^{\uparrow } $ 、自旋向下通道的带隙$ {E}_{\text{g}}^{\downarrow } $ 、体系的磁特性以及导电特性Table 3. Band gaps in the spin-up channel
$ {E}_{\text{g}}^{\uparrow } $ , spin-down channel$ {E}_{\text{g}}^{\downarrow } $ , the magnetic and electronic properties.体系类型 $ {E}_{\text{g}}^{\uparrow } $/eV $ {E}_{\text{g}}^{\downarrow } $/eV 磁特性 导电特性 未掺杂 1.813 1.813 非磁性 半导体 Mn掺杂 0.018 1.125 磁性 半金属 Tc掺杂 1.416 1.416 非磁性 N型半导体 Re掺杂 1.516 1.516 非磁性 N型半导体 -
[1] Žutić I, Fabian J, Sarma S D 2004 Rev. Mod. Phys. 76 323Google Scholar
[2] De Groot R, Mueller F, van Engen P, Buschow K 1983 Phys. Rev. Lett. 50 2024Google Scholar
[3] 何聪丽, 许洪军, 汤建, 王潇, 魏晋武, 申世鹏, 陈庆强, 邵启明, 于国强, 张广宇, 王守国 2021 物理学报 70 127501Google Scholar
He C L, Xu H J, Tang J, Wang X, Wei J W, Shen S P, Chen Q Q, Shao Q M, Yu G Q, Zhang G Y Wang S G 2021 Acta Phys. Sin. 70 127501Google Scholar
[4] 俞洋, 张文杰, 赵婉莹, 林贤, 金钻明, 刘伟民, 马国宏 2019 物理学报 68 017201Google Scholar
Yu Y, Zhang W J, Zhao W Y, Lin X, Jin Z M, Liu W M, Ma G H 2019 Acta Phys. Sin. 68 017201Google Scholar
[5] Tiwari S K, Sahoo S, Wang N, Huczko A 2020 J. Sci.: Adv. Mater. Dev. 5 10Google Scholar
[6] Shen C, Ying J, Liu L, Liu J, Li N, Wang S, Tang J, Zhao Y, Chu Y, Watanabe K 2021 Chin. Phys. Lett. 38 047301Google Scholar
[7] Du J, Lyu B, Shan W, Chen J, Zhou X, Xie J, Deng A, Hu C, Liang Q, Xie G 2021 Chin. Phys. Lett. 38 056301Google Scholar
[8] Zhang X, Pan G, Zhang Y, Kang J, Meng Z Y 2021 Chin. Phys. Lett. 38 077305Google Scholar
[9] Fu Q, Han J, Wang X, Xu P, Yao T, Zhong J, Zhong W, Liu S, Gao T, Zhang Z 2021 Adv. Mater. 33 1907818Google Scholar
[10] Liu Y, Gao Y, Zhang S, He J, Yu J, Liu Z 2019 J. Nano Res. 12 2695Google Scholar
[11] Hu Z, Wu Z, Han C, He J, Ni Z, Chen W 2018 Chem. Soc. Rev. 47 3100Google Scholar
[12] Luan Q, Yang C L, Wang M S, Ma X G 2017 Chin. J. Phys. 55 1930Google Scholar
[13] Chen Y, Chen Y, Ning J, Chen L, Zhuang W, He L, Zhang R, Xu Y, Wang X 2020 Chin. Phys. Lett. 37 017104Google Scholar
[14] Zhao Y, Liu B, Yang J, He J, Jiang J 2020 Chin. Phys. Lett. 37 088501Google Scholar
[15] Zhang M L, Zou X M, Liu X Q 2020 Chin. Phys. Lett. 37 118501Google Scholar
[16] Zhou S H, Zhou C W, Yang X D, Li Y, Zhong J Q, Mao H Y 2021 Chin. Phys. Lett. 38 057305Google Scholar
[17] Wang Z, Qiu J J, Wang X, Zhang Z, Chen Y, Huang X, Huang W 2018 Chem. Soc. Rev. 47 6128Google Scholar
[18] 周倩玉, 李鑫, 刘灏, 戴三瑜, 王世锋 2021 电子元件与材料 40 10Google Scholar
Zhou Q Y, Li X, Liu H, Dai S Y, Wang S F 2021 Electr. Comp. Mater 40 10Google Scholar
[19] Rapoport L, Leshchinsky V, Lapsker I, Volovik Y, Nepomnyashchy O, Lvovsky M, Popovitz-Biro R, Feldman Y, Tenne R 2003 wear 255 785Google Scholar
[20] Farkous M, Bikerouin M, Thuan D V, Benhouria Y, El-Yadri M, Feddi E, Erguig H, Dujardin F, Nguyen C V, Hieu N V 2020 Physica E 116 113799Google Scholar
[21] 令维军, 夏涛, 董忠, 刘勍, 路飞平, 王勇刚 2017 物理学报 66 114207Google Scholar
Lin W J, Xia T, Dong Z, Liu Q, Lu F P, Wang Y G 2017 Acta Phys. Sin. 66 114207Google Scholar
[22] Sun S, Dang J, Xie X, Yu Y, Yang L, Xiao S, Wu S, Peng K, Song F, Wang Y 2020 Chin. Phys. Lett. 37 087801Google Scholar
[23] Zhang D, Cao Y, Yang Z, Wu J 2020 ACS Appl. Mater. Interfaces 12 11979Google Scholar
[24] Zhou Q, Duan J, Yang X, Duan Y, Tang Q 2020 Angew. Chem. 132 22181Google Scholar
[25] Kang K, Fu S, Shayan K, Anthony Y, Dadras S, Yuzan X, Kazunori F, Terrones M, Zhang W, Strauf S 2020 Nanotechnol. 32 095708Google Scholar
[26] Xiao S L, Yu W Z, Gao S P 2016 Surf. Sci. 653 107Google Scholar
[27] Xie L Y, Zhang J M 2017 Superlattice Microst. 112 224Google Scholar
[28] Wang M M, Zhang J M, Ali A, Wei X M, Huang Y H 2021 Physica E Low Dimens. Syst. Nanostruct. 134 114917Google Scholar
[29] Urbanová V, Lazar P, Antonatos N, Sofer Z k, Otyepka M, Pumera M 2020 ACS Appl. Mater. Interfaces 12 20383Google Scholar
[30] Singh N, Schwingenschlögl U 2016 ACS Appl. Mater. Interfaces 8 23886Google Scholar
[31] Hafner J 2008 J. Comput. Chem 29 2044Google Scholar
[32] Gross E K, Dreizler R M 2013 Density Functional Theory (Vol. 337) (Springer Science & Business Media)
[33] Bishal G 2019 Comput. Condens. Matter 18 e00352Google Scholar
[34] Zhu Y Y, Zhang J M 2018 Superlattice Microst. 117 155Google Scholar
[35] Gillan M 1989 J. Phys. Condens. Matter 1 689Google Scholar
[36] Dolui K, Rungger I, Pemmaraju C D, Sanvito S 2013 Phys. Rev. B 88 075420Google Scholar
[37] Yang Y, Feng Z Y, Zhang J M 2019 J. Magn. Magn. Mater. 486 165255Google Scholar
[38] Zhu Y Y, Zhang J M 2017 Superlattice Microst. 112 619Google Scholar
[39] Manchon A, Koo H C, Nitta J, Frolov S, Duine R 2015 Nat. Mater. 14 871Google Scholar
[40] Yang G, Gao S P 2021 Nanoscale 13 17057Google Scholar
[41] Qiu B, Zhao X, Hu G, Yue W, Yuan X, Ren J 2020 Physica E Low Dimens. Syst. Nanostruct. 116 113729Google Scholar
[42] Shu H 2020 Mater. Sci. Eng. B 261 114672Google Scholar
[43] Cong C, Shang J, Wang Y, Yu T 2018 Adv. Opt. Mater. 6 1700767Google Scholar
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