-
范德华异质结构为设计二维材料的电子、自旋特性提供了丰富的平台.解除谷简并是利用谷自由度处理和存储谷电子信息的必要条件，二维范德华异质结构中的邻近效应为定制邻近材料的电子能带结构提供了可控的方法.本文基于第一性原理计算，研究了 WSeTe/CrI3 范德华异质结的电子能带结构.通过施加垂直应变与改变衬底磁矩方向对能谷进行调控.单层WSeTe在K与K'存在一对简并能谷，在自旋轨道耦合作用与磁性衬底CrI3邻近效应作用下会产生较大的谷劈裂和谷极化.异质结产生的谷极化为25 meV.施加垂直应变可以有效的调节能谷极化，减小层间距可以增加谷极化.此外，衬底磁矩方向变化可以有效调控谷极化的方向和大小.本文的研究结果为谷自由度的调控提供了一个有效的方法，为谷电子学和自旋电子学的应用提供了新的途径.The valley degree of freedom, in addition to charge and spin, can be used to process information and to perform logic operations with the advantage of low power consumption and high speed. The effective manipulation of valley degrees of freedom is essential for their practical applications in valleytronics and spintronics. This study investigates effective strategies for the valley manipulation of the WSeTe/CrI3 van der Waals heterojunction with approximate 2% lattice mismatch by the first-principles calculations. The valley degree of freedom in WSeTe can be modulated by the mag-netism of Cr atoms in the substrate via the magnetic proximity effect, including the vertical strain method and the rotation of the magnetic moments of Cr atoms. First-principles calculations were performed by using the VASP software package with the generalized gradient approximation functional in PerdewBurke-Ernzerhof (PBE) form. The spin-orbit coupling was considered when calculating the band structure to investigate the valley properties. The dependence of valley polarization on vertical strain and the magnetic moment direction of the substrate have been systematically analyzed. There are two distinct stacking configurations for the WSeTe/CrI3 het-erojunction with Te/Se atom at the interface, namely Te-stacking and Se-stacking. While single layer of WSeTe does not have valley polarization, the Te-stacking and Se-stacking WSeTe/CrI3 heterojunctions exhibit valley polarizations of 25 meV and 2 meV, respectively, which is under the combined influence of spin-orbit coupling and the proximity effect from the magnetic substrate CrI3, indicating the importance of the stacking configuration. The Te-stacking configuration of the heterojunction has a larger valley polarization due to stronger orbital hybridization between W atoms in WSeTe layer and Cr atoms in CrI3 layer. The application of vertical strain, which ef-fectively tunes the interlayer distance, significantly regulates the valley polarization. Specifically, the valley polarization is increased to 59 meV when the interlayer dis-tance is decreased by 0.5 Å, while it decreases to 10 meV when the interlayer distance is increased by 0.5 Å. Additionally, when the magnetic moment of the CrI3 substrate is rotated by 360°, the valley polarization varies between -25 meV and 25 meV. It reaches maximum when the magnetic moment is aligned along the out-of-plane direc-tion. In conclusion, this study demonstrates that the valley degree of freedom in the WSeTe/CrI3 van der Waals heterojunction can be effectively manipulated by adjusting the interlayer distance through vertical strain and by controlling the magnetic moment direction of the substrate. These findings provide valuable insights into the design and application of valleytronic and spintronic devices based on two-dimensional van der Waals heterostructures.
-
Keywords:
- valley /
- heterojunction /
- magnetic proximity /
- first principles
-
[1] Gunawan O, Shkolnikov Y P, Vakili K, Gokmen T, De Poortere E P, Shayegan M 2006 Phys. Rev. Lett. 97 186404
[2] Rycerz A, Tworzydło J, Beenakker C W J 2007 Nat. Phys. 3 172
[3] Sun Z H, Guan H M, Fu L, Shen B, Tang N 2021 Acta Phys. Sin. 70 027302 (in Chinese) [孙真昊, 管鸿明, 付雷, 沈波, 唐宁 2021 70 027302]
[4] Schaibley J R, Yu H, Clark G, Rivera P, Ross J S, Seyler K L, Yao W, Xu X 2016 Nat. Rev. Mater. 1 16055
[5] Xiao D, Liu G B, Feng W, Xu X, Yao W 2012 Phys. Rev. Lett. 108 196802
[6] Aivazian G, Gong Z, Jones A M, Chu R L, Yan J, Mandrus D G, Zhang C, Cobden D, Yao W, Xu X 2015 Nat. Phys. 11 148
[7] MacNeill D, Heikes C, Mak K F, Anderson Z, Kormanyos A, Zolyomi V, Park J, Ralph D C 2015 Phys. Rev. Lett. 114 037401
[8] Srivastava A, Sidler M, Allain A V, Lembke D S, Kis A, Imamoğlu A 2015 Nat. Phys. 11 141
[9] Xu S, Si C, Li Y, Gu B L, Duan W 2021 Nano Lett. 21 1785
[10] Cheng Y C, Zhang Q Y, Schwingenschlögl U 2014 Phys. Rev. B 89 155429
[11] Ramasubramaniam A, Naveh D 2013 Phys. Rev. B 87 195201
[12] Zhang D H, Zhou W Z, Li A L, Ouyang F P 2021 Acta Phys. Sin. 70 096301 (in Chinese) [张德贺, 周文哲, 李奥林, 欧阳方平 2021 70 096301]
[13] Qi J, Li X, Niu Q, Feng J 2015 Phys. Rev. B 92 121403
[14] Zhang Q, Yang S A, Mi W, Cheng Y, Schwingenschlogl U 2016 Adv. Mater. 28 959
[15] Zheng G, Zhang B, Duan H, Zhou W, Ouyang F 2023 Physica E 148 115616
[16] Deng L M, Si J S, Wu X C, Zhang W B 2022 Acta Phys. Sin. 71 147101 (in Chinese) [邓霖湄, 司君山, 吴绪才, 张卫兵 2022 71 147101]
[17] Yao W, Xiao D, Niu Q 2008 Phys. Rev. B Condens. Matter and Mater. Phys. 77 235406
[18] Mak K F, He K, Shan J, Heinz T F 2012 Nat. Nanotechnol. 7 494
[19] Liu H, Zhang Z, Li Y, Wu Y, Wu Z, Li X, Zhang C, Xu F, Kang J 2023 Adv. Photon. Nexus 2 026007
[20] Stier A V, McCreary K M, Jonker B T, Kono J, Crooker S A 2016 Nat. Commun. 7 10643
[21] Abid A, Haneef M, Ali S, Dahshan A 2022 J. Solid State Chem. 311 123159
[22] Mehdipour H, Kratzer P 2024 Phys. Rev. B 109 085425
[23] Sattar S, Larsson J A, Canali C M, Roche S, Garcia J H 2022 Phys. Rev. B 105 L041402
[24] Norden T, Zhao C, Zhang P, Sabirianov R, Petrou A, Zeng H 2019 Nat. Commun. 10 4163
[25] Hu T, Zhao G, Gao H, Wu Y, Hong J, Stroppa A, Ren W 2020 Phys. Rev. B 101 125401
[26] Zhang W, Zhu H, Zhang W, Wang J, Zhang T, Yang S, Shao B, Zuo X 2024 Appl. Surf. Sci. 647 158986
[27] Ye Y, Xiao J, Wang H, Ye Z, Zhu H, Zhao M, Wang Y, Zhao J, Yin X, Zhang X 2016 Nat. Nanotechnol. 11 598
[28] Lu A Y, Zhu H, Xiao J, Chuu C P, Han Y, Chiu M H, Cheng C C, Yang C W, Wei K H, Yang Y, Wang Y, Sokaras D, Nordlund D, Yang P, Muller D A, Chou M Y, Zhang X, Li L J 2017 Nat. Nanotechnol. 12 744
[29] Zhang J, Jia S, Kholmanov I, Dong L, Er D, Chen W, Guo H, Jin Z, Shenoy V B, Shi L, Lou J 2017 ACS Nano 11 8192
[30] Hajra D, Sailus R, Blei M, Yumigeta K, Shen Y, Tongay S 2020 ACS Nano 14 15626
[31] Trivedi D B, Turgut G, Qin Y, Sayyad M Y, Hajra D, Howell M, Liu L, Yang S, Patoary N H, Li H, Petric M M, Meyer M, Kremser M, Barbone M, Soavi G, Stier A V, Muller K, Yang S, Esqueda I S, Zhuang H, Finley J J, Tongay S 2020 Adv. Mater. 32 2006320
[32] Yang S Y, Shi D R, Wang T, Yue X Y, Zheng L, Zhang Q H, Gu L, Yang X Q, Shadike Z, Li H, Fu Z-W 2020 J. Mater. Chem. A 8 25739
[33] Guo S-D, Zhu J-X, Yin M-Y, Liu B-G 2022 Phys. Rev. B 105 104416
[34] Zhang L, Zhao Y, Liu Y, Gao G 2023 Nanoscale 15 18910
[35] Chen Y, Zhao X, An Y 2024 Phys. Rev. B 109 125421
[36] Kresse, Furthmuller 1996 Phys. Rev. B Condens. Matter 54 11169
[37] Grimme S, Antony J, Ehrlich S, Krieg H 2010 J. Chem. Phys. 132 154104
[38] Monkhorst H J, Pack J D 1976 Phys. Rev. B 13 5188
[39] Dudarev S L, Botton G A, Savrasov S Y, Humphreys C, Sutton A P 1998 Phys. Rev. B 57 1505
[40] Kim H J https://github.com/Infant83/VASPBERRY [2024-7-11]
[41] Hu T, Jia F H, Zhao G D, Wu J Y, Stroppa A, Ren W 2018 Phys. Rev. B 97 235404
[42] Webster L, Yan J-A 2018 Phys. Rev. B 98 144411
[43] Ma Z, Huang P, Li J, Zhang P, Zheng J, Xiong W, Wang F, Zhang X 2022 Npj Comput. Mater. 8 11
[44] Zhang H, Li Y, Hou J, Du A, Chen Z 2016 Nano Lett. 16 6124
[45] Shao Y, Shao M, Kawazoe Y, Shi X, Pan H 2018 J. Mater. Chem. A 6 10226
[46] Yang C, Li J, Liu X, Bai C 2023 Phys. Chem. Chem. Phys. 25 28796
计量
- 文章访问数: 80
- PDF下载量: 2
- 被引次数: 0
下载:
