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(111)取向的钙钛矿异质结具有独特的六角蜂窝状双层结构, 展现出丰富独特的物理现象, 因而近年来得到越来越多的关注. 本文利用第一性原理计算研究了(111)取向的(SrVO3)5/(SrTiO3)1异质结, 计算结果表明该体系为半金属铁磁体. 进一步的研究表明该体系的电、磁性质可以通过施加面内应变和界面元素掺杂进行调控: 在4%的面内压缩应变到2%的面内拉伸应变范围内, 该体系保持铁磁半金属性质, V 3d电子是体系半金属性的主要来源; 当面内压缩应变增加到8%或面内拉伸应变增加到4%时, 该体系的基态变为反铁磁绝缘体; 通过异质结界面处Ti-V阳离子的混合掺杂, 该体系可以实现从铁磁半金属向铁磁绝缘体的转变. 本文的研究结果表明, 该体系在自旋电子学领域具有很高的应用潜力, 本文研究为利用(SrVO3)5/(SrTiO3)1(111)异质结探索量子相变提供了理论参考.Perovskite heterostructure has a honeycomb lattice when a bilayer along the [111] direction is considered. The material usually presents a wealth of unique properties. Recently, (111)-oriented perovskite heterojunctions have received more and more attention. In this work, the first-principle calculations are employed to investigate the electronic and magnetic properties of (SrVO3)5/(SrTiO3)1 (111) heterostructure. The calculations show that the ground state of (SrVO3)5/(SrTiO3)1 (111) heterostructure is a half-metallic ferromagnet. Further study reveals the existence of different correlated-electron ground states in (SrVO3)5/(SrTiO3)1 (111) heterostructure, and they can be tuned by changing in-plane strain and interfacial cation intermixing. This system can keep half-metallic properties under difffferent in-plane strains from –4% to 2%. The half-metallic properties mainly come from V 3d electrons. The ground state of the system can evolve from a half-metal to a antiferromagnetic insulator if the in-plane compressive (tensile) strain is added up to 8% (4%). The interfacial Ti-V intermixing can destroy the original half-metallic properties, and the system exhibits a ferromagnetic insulator phase. These results demonstrate that the system has potential applications in the field of spintronics, and provide a theoretical reference for the use of (SrVO3)5/(SrTiO3)1 (111) heterostructures to explore quantum phase transitions.
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Keywords:
- heterostructures /
- in-plane strain /
- metal-insulator transition /
- half-metallic ferromagnets
[1] Ohtomo A, Hwang H Y 2004 Nature 427 423Google Scholar
[2] Zhang X J, Chen P, Liu B G 2017 J. Mater. Chem. C 5 9898Google Scholar
[3] Davis S, Huang Z, Han K, Ariando, Venkatesan T, Chandrasekhar V 2018 Phys. Rev. B 98 024504
[4] Kim D H, Kim D W, Kang B S, Noh T W, Lee D R, Lee K B, Lee S J 2000 Solid State Commun. 114 473Google Scholar
[5] Dai Q, Lüders U, Frésard R, Eckern U, Schwingenschlögl U 2018 Adv. Mater. Interfaces 5 1701169Google Scholar
[6] Pardo V, Pickett W E 2010 Phys. Rev. B 81 245117Google Scholar
[7] James A D N, Aichhorn M, Laverock J 2021 Phys. Rev. Res. 3 023149Google Scholar
[8] Yang Z, Ko C, Ramanathan S 2011 Annu. Rev. Mater. Res. 41 337Google Scholar
[9] Xu R, Ji Y, Bouchilaoun R, Qian F, Li M, Zhang X, Tang R, Zhao R, Misra S, Wang H, Li W, Kan C, Shi D, Fan J, Yang H 2019 Ceram. Int. 45 11304Google Scholar
[10] Roth J, Kuznetsova T, Miao L X, Pogrebnyakov1 A, Alem1 N, Engel-Herbert R 2021 APL Mater. 9 021114Google Scholar
[11] Mitsuhashi T, Minohara M, Yukawa R, Kitamura M, Horiba K, Kobayashi M, Kumigashira H 2016 Phys. Rev. B 94 125148Google Scholar
[12] Jacobs R, Booske J, Morgan D 2016 Adv. Funct. Mater. 26 5471Google Scholar
[13] 袁烺, 肖嘉慧, 谢颖 2017 中国科技论文 12 2826Google Scholar
Yuan L, Xiao J H, Xie Y 2017 Chin. Sci. Paper 12 2826Google Scholar
[14] Shen M L, Weng Y K, Yi Y W, Geng Q F, Yan W, Wang H Y, Yang J P, Li X 2019 J. Appl. Phys. 126 085307Google Scholar
[15] Weng Y K, Zhang J J, Gao B, Dong S 2017 Phys. Rev. B 95 155117Google Scholar
[16] Xiao D, Zhu W, Ran Y, Nagaosa N, Okamoto S 2011 Nat. Commun. 2 1Google Scholar
[17] Okamoto S, Zhu W, Nomura Y, Arita R, Xiao D, Nagaosa N 2014 Phys. Rev. B 89 195121Google Scholar
[18] Chen R, Lee S B, Balents L 2013 Phys. Rev. B 87 161119
[19] Doennig D, Pickett W E, Pentcheva R 2014 Phys. Rev. B 89 121110
[20] Du Y L, Wang C L, Li J C, Zhang X Z, Wang F N, Zhu Y H, Yin N, Mei L M 2015 Comput. Mater. Sci. 99 57Google Scholar
[21] 李永宁, 谢逸群, 王音 2021 物理学报 70 227701Google Scholar
Li Y N, Xie Y Q, Wang Y 2021 Acta Phys. Sin. 70 227701Google Scholar
[22] 胡海洋, 陈吉堃, 邵飞, 吴勇, 孟康康, 李志鹏, 苗君, 徐晓光, 王嘉鸥, 姜勇 2019 物理学报 68 026701Google Scholar
Hu H Y, Chen J K, Shao F, Wu Y, Meng K K, Li Z P, Miao J, Xu X G, Wang J O, Jiang Y 2019 Acta Phys. Sin. 68 026701Google Scholar
[23] Kalabukhov A S, Boikov Y A, Serenkov I T, Sakharov V I, Popok V N, Gunnarsson R, Borjesson J, Ljustina N, Olsson E, Winkler D, Claeson T 2009 Phys. Rev. Lett. 103 146101Google Scholar
[24] Qiao L, LDroubay T C, Shutthanandan V, Zhu Z, Sushko P V, Chambers S A 2010 J. Phys. Condens. Matter 22 312201Google Scholar
[25] Li J, Yin D, Li Q, Sun R 2017 Phys. Chem. Chem. Phys. 19 6945Google Scholar
[26] Kresse G, Furthmüller J 1996 Phys. Rev. B 54 11169Google Scholar
[27] Perdew J P, Burke K, Ernzerhof M 1996 Phys. Rev. Lett. 77 3865Google Scholar
[28] Blöchl P E 1994 Phys. Rev. B 50 17953Google Scholar
[29] Anisimov V I, Zaanen J, Andersen O K 1991 Phys. Rev. B 44 943Google Scholar
[30] Du Y L, Wang C L, Li J C, Xu P P, Zhang X H, Liu J, Su W B, Mei L M 2014 Chin. Phys. B 23 087302Google Scholar
[31] Park S Y, Kumar A, Rabe K M 2017 Phys. Rev. Lett. 118 087602Google Scholar
[32] Monkhorst H J, Pack J D 1976 Phys. Rev. B 13 5188Google Scholar
[33] Shein I R, Kozhevnikov V L, Ivanovskii A L 2008 Solid State Sci. 10 217Google Scholar
[34] Chandra H K, Guo G Y 2017 Phys. Rev. B 95 134448
[35] Shein I R, Ivanovskii A L 2007 Phys. Lett. A 371 155Google Scholar
[36] Musa Saad H E M 2021 Bull. Mater. Sci. 44 1Google Scholar
[37] Beltrán J I, Muñoz M C 2017 Phys. Rev. B 95 245120Google Scholar
[38] Du Y L, Bu H X, Ji C J, Zhang X M, Li C L, Fang X N 2019 Phys. Chem. Chem. Phys. 21 18170Google Scholar
[39] De Luca G M, Di Capua R, Di Gennaro E, Sambri A, Miletto Granozio F, Ghiringhelli G, Betto D, Piamonteze C, Brookes N B, Salluzzo M 2018 Phys. Rev. B 98 115143Google Scholar
[40] Ye H S, Zhu Y J, Bai D M, Zhang J T, Wu X S, Wang J L 2021 Phys. Rev. B 103 035423Google Scholar
[41] Yoshida T, Kobayashi M, Yoshimatsu K, Kumigashira H, Fujimori A 2016 J. Electron. Spectrosc. 208 11Google Scholar
[42] Ma H J H, Zhou J, Yang M, Liu Y, Zeng S W, Zhou W X, Zhang L C, Venkatesan T, FengY P, Ariando A 2017 Phys. Rev. B 95 155314Google Scholar
[43] Liu Z T Y, Podraza N J, Khare S V, Sarin P 2018 Comput. Mater. Sci. 144 139Google Scholar
[44] Oshima M 2014 Appl. Sci. Converg. Technol. 23 317Google Scholar
[45] Wang J, Gauquelin N, Huijben M, Verbeeck J, Rijnders G, Koster G 2020 Appl. Phys. Lett. 117 133105Google Scholar
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图 1 (a), (b) (SVO)5/(STO)1 (111)异质结的(a)俯视图和(b)侧视图; (c) 沿c轴方向, 相邻原子层之间的距离; (d) SrO3原子层中锶离子相对于氧离子在c轴方向的位移, ΔZ = Z(Sri) – Z(Oi), 其中Z(Sri)是第i层SrO3中锶离子的纵坐标值, Z(Oi)是第i层SrO3中氧离子的纵坐标平均值
Fig. 1. (a) Top view of the (SVO)5/(STO)1(111) heterostructure with in-plane 1 × 1 unit cells; (b) side view of (SVO)5/(STO)1(111) heterostructure; (c) the interplanar distance between consecutive planes; (d) the displacement of Sr cation relative to O ions in each SrO3 layers, ΔZ = Z(Sri) – Z(Oi), where Z(Sri) is the value of the Sr cation and Z(Oi) is the average value of the O atoms in a given SrO3 layer i along the c axis.
图 2 (a) (SVO)5/(STO)1(111)异质结费米面附近的能带结构, 高对称点如图中第一布里渊区所示; (b) 费米面附近的总态密度图, 费米能位于0 eV处(用黑色虚线表示); (c) (SVO)5/(STO)1(111)各原子层在费米面附近的态密度图, 图中自旋向上的电子态密度由浅灰色区域表示, 自旋向下的电子态密度由深灰色区域表示, 黑色虚线表示费米能级; (d) 费米面附近([EF –1.5 eV, EF])的电荷密度图, 图中三维电荷密度的isosurface值取0.015 e/bohr3
Fig. 2. (a) Band structures of (SVO)5/(STO)1(111) along with the special points in the Brillouin zone. The inset shows the Brillouin zone and the special points. (b) Total density of states (TDOS) near the Fermi level. The Fermi level is located at 0 eV (dotted black line). (c) Layer-resolved partial density of states (PDOS) of (SVO)5/(STO)1(111). (d) Projections of the carrier density (yellow contour) of (SVO)5/(STO)1(111) heterostructure. The isosurface values are chosen as 0.015 e/bohr3. The carrier densities are calculated from contributions within an energy window of [EF –1.5 eV, EF].
图 3 (a) V, Ti, Sr, O原子的态密度图; (b) V原子3 d轨道的分波态密度图, 其中, V1, V2, V3与图1(b)中标注一致; (c) O原子2p轨道的分波态密度图; (d) Ti原子3d轨道的分波态密度图
Fig. 3. (a) Densities of states near the Fermi level of V, Ti, Sr and O. (b) Partial densities of states (PDOS) of V 3d orbitals. V1, V2, V3 are the same as those in Fig. 1(b). (c) PDOS of the O 2p orbitals. (d) PDOS of the Ti 3d orbitals.
图 4 (a) 面内压缩应变为8%和面内拉伸应变为4%时能量最低的反铁磁序. 红色小球代表自旋向上的V原子, 绿色小球代表自旋向下的V原子, 蓝色小球代表Ti原子. (b) 在不同的面内应变条件下, 沿c轴方向各原子层之间的距离
Fig. 4. (a) The most stable AFM structure of (SVO)5/(STO)1(111) under the in-plane compressive (tensile) strain of 8% (4%). The red and green balls represent the spin-up and spin-down V atoms, respectively. Blue balls represent Ti atoms. (b) The interplanar distance along the c axis between consecutive planes under different in-plane strains.
图 5 (SVO)5/(STO)1(111)异质结在不同面内应变下费米面附近的能带结构和总态密度图 (a) η = –8%; (b) η = –7%; (c) η = –4%; (d) η = –2%; (e) η = 2%; (f) η = 4%. 高对称点如图2(a)中第一布里渊区所示, 对应面内应变下的总态密度图显示在能带图的下面. 黑色实线和红色实线分别代表自旋向上和自旋向下, 费米能级用虚线表示
Fig. 5. Band structures and total density of states near the Fermi level of (SVO)5/(STO)1(111) under different in-plane strains: (a) η = –8%; (b) η = –7%; (c) η = –4%; (d) η = –2%; (e) η = 2%; (f) η = 4%. The Brillouin zone is the same as that in Fig. 2(a). Black and red lines are spin-up and spin-down states, respectively. The Fermi level is located at 0 eV (dotted black line).
图 6 不同面内应变下(SVO)5/(STO)1(111)异质结中各原子的态密度图 (a) η = –8%; (b) η = –7%; (c) η = –4%; (d) η = –2%; (e) η = 2%; (f) η = 4%. 不同颜色的实线代表不同原子的态密度图. 态密度图中上部为上自旋态密度, 下部为下自旋态密度, 费米能级用黑色虚线表示
Fig. 6. DOS near the Fermi level of the atoms in (SVO)5/(STO)1(111) under different in-plane strains: (a) η = –8%; (b) η = –7%; (c) η = –4%; (d) η = –2%; (e) η = 2%; (f) η = 4%. Different orbitals are marked by different colored lines. The Fermi level is indicated by the dashed line.
图 7 不同面内应变下铁磁半金属(SVO)5/(STO)1(111)异质结中费米面附近([EF –1.5 eV, EF])的电荷密度图和各V原子的磁矩 (a) η = –4%; (b) η = –2%; (c) η = 0%; (d) η = 2%. 图中三维电荷密度的isosurface值取 0.015 e/bohr3
Fig. 7. Projections of the carrier density (yellow contour) and magnetic moments of V atoms of (SVO)5/(STO)1(111) heterostructure under different in-plane strains: (a) η = –4%; (b) η = –2%; (c) η = 0%; (d) η = 2%. The atoms are not shown. The isosurface values are chosen as 0.015 e/bohr3. The carrier densities are calculated from contributions within an energy window of [EF –1.5 eV, EF]
图 8 不同面内应变下(SVO)5/(STO)1(111)异质结中V 3d轨道的态密度图 (a) η = –8%; (b) η = –7%; (c) η = –4%; (d) η = –2%; (e) η = 2%; (f) η = 4%. 不同颜色的实线代表不同轨道; 态密度图中上部为上自旋态密度, 下部为下自旋态密度, 费米能级用虚线表示
Fig. 8. Projected density of states of V 3d near the Fermi level of (SVO)5/(STO)1(111) under different in-plane strains: (a) η = –8%; (b) η = –7%; (c) η = –4%; (d) η = –2%; (e) η = 2%; (f) η = 4%. Different orbitals are marked by different colored lines. The Fermi level is indicated by the dashed line.
图 9 (a) 界面Ti-V扩散掺杂模型Ⅰ的(SVO)5/(STO)1(111)侧视图(图中只显示Ti和V原子); (b) 模型Ⅰ费米面附近的总态密度, 费米能位于0 eV处(用黑色虚线表示); (c) 模型Ⅰ各原子的态密度图; (d) 界面Ti-V扩散掺杂模型Ⅱ的(SVO)5/(STO)1 (111)侧视图(图中只显示Ti和V原子); (e) 模型Ⅱ费米面附近的总态密度, 费米能位于0 eV处(用黑色虚线表示); (f) 模型Ⅱ各原子的态密度图, 不同颜色的实线代表不同原子的态密度图. 态密度图中上部为上自旋态密度, 下部为下自旋态密度, 费米能级用虚线表示
Fig. 9. (a) Side view of (SVO)5/(STO)1(111) heterostructure Ⅰ with interfacial Ti-V intermixing; (b) total density of states of heterostructure Ⅰ near the Fermi level; (c) DOS of atoms in heterostructure Ⅰ near the Fermi level; (d) side view of (SVO)5/(STO)1 (111) heterostructure Ⅱ with interfacial Ti-V intermixing; (e) total density of states of heterostructure Ⅱ near the Fermi level; (f) DOS of atoms in heterostructure Ⅱ near the Fermi level. Different orbitals are marked by different colored lines. The Fermi level is indicated by the dashed line.
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[1] Ohtomo A, Hwang H Y 2004 Nature 427 423Google Scholar
[2] Zhang X J, Chen P, Liu B G 2017 J. Mater. Chem. C 5 9898Google Scholar
[3] Davis S, Huang Z, Han K, Ariando, Venkatesan T, Chandrasekhar V 2018 Phys. Rev. B 98 024504
[4] Kim D H, Kim D W, Kang B S, Noh T W, Lee D R, Lee K B, Lee S J 2000 Solid State Commun. 114 473Google Scholar
[5] Dai Q, Lüders U, Frésard R, Eckern U, Schwingenschlögl U 2018 Adv. Mater. Interfaces 5 1701169Google Scholar
[6] Pardo V, Pickett W E 2010 Phys. Rev. B 81 245117Google Scholar
[7] James A D N, Aichhorn M, Laverock J 2021 Phys. Rev. Res. 3 023149Google Scholar
[8] Yang Z, Ko C, Ramanathan S 2011 Annu. Rev. Mater. Res. 41 337Google Scholar
[9] Xu R, Ji Y, Bouchilaoun R, Qian F, Li M, Zhang X, Tang R, Zhao R, Misra S, Wang H, Li W, Kan C, Shi D, Fan J, Yang H 2019 Ceram. Int. 45 11304Google Scholar
[10] Roth J, Kuznetsova T, Miao L X, Pogrebnyakov1 A, Alem1 N, Engel-Herbert R 2021 APL Mater. 9 021114Google Scholar
[11] Mitsuhashi T, Minohara M, Yukawa R, Kitamura M, Horiba K, Kobayashi M, Kumigashira H 2016 Phys. Rev. B 94 125148Google Scholar
[12] Jacobs R, Booske J, Morgan D 2016 Adv. Funct. Mater. 26 5471Google Scholar
[13] 袁烺, 肖嘉慧, 谢颖 2017 中国科技论文 12 2826Google Scholar
Yuan L, Xiao J H, Xie Y 2017 Chin. Sci. Paper 12 2826Google Scholar
[14] Shen M L, Weng Y K, Yi Y W, Geng Q F, Yan W, Wang H Y, Yang J P, Li X 2019 J. Appl. Phys. 126 085307Google Scholar
[15] Weng Y K, Zhang J J, Gao B, Dong S 2017 Phys. Rev. B 95 155117Google Scholar
[16] Xiao D, Zhu W, Ran Y, Nagaosa N, Okamoto S 2011 Nat. Commun. 2 1Google Scholar
[17] Okamoto S, Zhu W, Nomura Y, Arita R, Xiao D, Nagaosa N 2014 Phys. Rev. B 89 195121Google Scholar
[18] Chen R, Lee S B, Balents L 2013 Phys. Rev. B 87 161119
[19] Doennig D, Pickett W E, Pentcheva R 2014 Phys. Rev. B 89 121110
[20] Du Y L, Wang C L, Li J C, Zhang X Z, Wang F N, Zhu Y H, Yin N, Mei L M 2015 Comput. Mater. Sci. 99 57Google Scholar
[21] 李永宁, 谢逸群, 王音 2021 物理学报 70 227701Google Scholar
Li Y N, Xie Y Q, Wang Y 2021 Acta Phys. Sin. 70 227701Google Scholar
[22] 胡海洋, 陈吉堃, 邵飞, 吴勇, 孟康康, 李志鹏, 苗君, 徐晓光, 王嘉鸥, 姜勇 2019 物理学报 68 026701Google Scholar
Hu H Y, Chen J K, Shao F, Wu Y, Meng K K, Li Z P, Miao J, Xu X G, Wang J O, Jiang Y 2019 Acta Phys. Sin. 68 026701Google Scholar
[23] Kalabukhov A S, Boikov Y A, Serenkov I T, Sakharov V I, Popok V N, Gunnarsson R, Borjesson J, Ljustina N, Olsson E, Winkler D, Claeson T 2009 Phys. Rev. Lett. 103 146101Google Scholar
[24] Qiao L, LDroubay T C, Shutthanandan V, Zhu Z, Sushko P V, Chambers S A 2010 J. Phys. Condens. Matter 22 312201Google Scholar
[25] Li J, Yin D, Li Q, Sun R 2017 Phys. Chem. Chem. Phys. 19 6945Google Scholar
[26] Kresse G, Furthmüller J 1996 Phys. Rev. B 54 11169Google Scholar
[27] Perdew J P, Burke K, Ernzerhof M 1996 Phys. Rev. Lett. 77 3865Google Scholar
[28] Blöchl P E 1994 Phys. Rev. B 50 17953Google Scholar
[29] Anisimov V I, Zaanen J, Andersen O K 1991 Phys. Rev. B 44 943Google Scholar
[30] Du Y L, Wang C L, Li J C, Xu P P, Zhang X H, Liu J, Su W B, Mei L M 2014 Chin. Phys. B 23 087302Google Scholar
[31] Park S Y, Kumar A, Rabe K M 2017 Phys. Rev. Lett. 118 087602Google Scholar
[32] Monkhorst H J, Pack J D 1976 Phys. Rev. B 13 5188Google Scholar
[33] Shein I R, Kozhevnikov V L, Ivanovskii A L 2008 Solid State Sci. 10 217Google Scholar
[34] Chandra H K, Guo G Y 2017 Phys. Rev. B 95 134448
[35] Shein I R, Ivanovskii A L 2007 Phys. Lett. A 371 155Google Scholar
[36] Musa Saad H E M 2021 Bull. Mater. Sci. 44 1Google Scholar
[37] Beltrán J I, Muñoz M C 2017 Phys. Rev. B 95 245120Google Scholar
[38] Du Y L, Bu H X, Ji C J, Zhang X M, Li C L, Fang X N 2019 Phys. Chem. Chem. Phys. 21 18170Google Scholar
[39] De Luca G M, Di Capua R, Di Gennaro E, Sambri A, Miletto Granozio F, Ghiringhelli G, Betto D, Piamonteze C, Brookes N B, Salluzzo M 2018 Phys. Rev. B 98 115143Google Scholar
[40] Ye H S, Zhu Y J, Bai D M, Zhang J T, Wu X S, Wang J L 2021 Phys. Rev. B 103 035423Google Scholar
[41] Yoshida T, Kobayashi M, Yoshimatsu K, Kumigashira H, Fujimori A 2016 J. Electron. Spectrosc. 208 11Google Scholar
[42] Ma H J H, Zhou J, Yang M, Liu Y, Zeng S W, Zhou W X, Zhang L C, Venkatesan T, FengY P, Ariando A 2017 Phys. Rev. B 95 155314Google Scholar
[43] Liu Z T Y, Podraza N J, Khare S V, Sarin P 2018 Comput. Mater. Sci. 144 139Google Scholar
[44] Oshima M 2014 Appl. Sci. Converg. Technol. 23 317Google Scholar
[45] Wang J, Gauquelin N, Huijben M, Verbeeck J, Rijnders G, Koster G 2020 Appl. Phys. Lett. 117 133105Google Scholar
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