电话：010-8264 9711

邮箱：xiaoran.liu@iphy.ac.cn

简介:

1988年生，2011年本科毕业于南京大学，获材料物理学士学位；2016年毕业于美国阿肯色大学（University of Arkansas），获物理学博士学位；2017-2021年在美国罗格斯大学（Rutgers University）任博士后研究员；2021年3月加入中国科学院物理研究所，任特聘研究员，博士生导师。

主要研究方向:

利用先进的薄膜沉积技术和基于大科学装置的尖端探测技术，研究关于量子材料薄膜/异质界面/超晶格的设计、制备、物性探究、性能调控等方面的前沿科学问题。

过去的主要工作及获得的成果:

过去的几年中，研究工作主要聚焦在强关联电子体系的一些前沿方向，如演生磁结构、自旋阻挫、量子自旋液体、界面电荷迁移、新型拓扑材料等。迄今，在Nature子刊、PNAS、Physical Review Letters、Nano Letters等国际知名期刊发表论文43篇，参与撰写邀请综述文章2篇。主要成果包括：（1）以具有亚铁磁性的铬氧化物CoCr₂O₄为典型，通过制备沿（111）方向的超薄薄膜，观测维度如何影响其长程磁序的形成。研究发现，当薄膜厚度降低至几个纳米时，系统的自旋阻挫显著增强，导致磁基态从原先的非共面-螺旋型结构变成了新奇的共面-倾角型结构。（2）在只有几个原子层厚度的（111）方向CoCr₂O₄超薄外延薄膜中，发现长程磁序竟然完全消失。并且材料在极低温时仍具有动态自旋、极大的简并度和自旋阻挫，揭示了一类新型的演生量子自旋液体的形成。（3）提出全新的“原位固相外延”生长方法，有效地解决了这类薄膜材料在沉积过程中出现的Ir大量缺失、薄膜均匀性差、易形成杂相等问题，首次制备出高质量烧绿石铱氧化物沿（111）方向的外延薄膜。（4）在钙钛矿结构的铱氧化物（SrIrO₃）/镍氧化物（LaNiO₃）人工晶格界面，发现显著的电荷转移和反常的自旋-轨道耦合抑制效应，进而揭示了由此产生的奇异Mott电子态。

代表性论文及专利:

1. X. Liu*, S. Fang*, Y. Fu, W. Ge, M. Kareev, J. Kim, Y. Choi, E. Karapetrova, Q. Zhang, L. Gu, E. Choi, F. Wen, J. Wilson, G. Fabbris, P. Ryan, J. Freeland, D. Haskel, W. Wu, J. Pixley, J. Chakhalian, Magnetic Weyl semimetallic phase in thin films of Eu₂Ir₂O₇, Physical Review Letters, 2021, 127: 277204.
2. X. Liu*, S. Singh, V. Drouin-Touchette, T. Asaba, J. Brewer, Q. Zhang, Y. Cao, B. Pal, S. Middey, P. Kumar, M. Kareev, L. Gu, D. D. Sarma, P. Shafer, E. Arenholz, J. Freeland, L. Li, D. Vanderbilt, J. Chakhalian, Proximate quantum spin liquid on designer lattice, Nano Letters, 2021, 21(5): 2010-2017.
3. X. Liu*, M. Kotigua, H. Kim, A. N’Diaye, Y. Choi, Q. Zhang, Y. Cao, M. Kareev, F. Wen, B. Pal, J. Freeland, L. Gu, D. Haskel, P. Shafer, E. Arenholz, K. Haule, D. Vanderbilt, K. M. Rabe*, J. Chakhalian, Interfacial charge-transfer Mott state in iridate-nickelate superlattices, Proceedings of the National Academy of Sciences of the United States of America, 2019, 116: 19863.
4. X. Liu*, S. Singh, B. Kirby, Z. Zhong, Y. Cao, B. Pal, M. Kareev, S. Middey, J. Freeland, P. Shafer, E. Arenholz, D. Vanderbilt, J. Chakhalian, Emergent magnetic state in (111)-oriented quasi-two-dimensional spinel oxides, Nano Letters, 2019, 19(12): 8381-8387.
5. X. Liu*, F. Wen, E. Karapetrova, J.-W. Kim, P. J. Ryan, J. Freeland, M. Terilli, T.-C. Wu, M. Kareev, J. Chakhalian, In-situ fabrication and transport properties of (111) Y₂Ir₂O₇ epitaxial thin film, Applied Physics Letters, 2020, 117: 041903. 【Editor's Pick】
6. X. Liu*, Y. Cao, B. Pal, S. Middey, M. Kareev, Y. Choi, P. Shafer, D. Haskel, E. Arenholz, J. Chakhalian, Synthesis and electronic properties of Ruddlesden-Popper strontium iridate epitaxial thin films stabilized by control of growth kinetics, Physical Review Materials, 2017, 1: 075004.
7. E. Abreu, D. Meyers, V. Thorsmolle, J. Zhang, X. Liu, K. Geng, J. Chakhalian, R. Averitt, Nucleation and growth bottleneck in the conductivity recovery dynamics of nickelate ultrathin films, Nano Letters, 2020, 20(10): 7422-7428.
8. J. Chakhalian*, X. Liu*, G. A. Fiete*, Strongly correlated and topological states in [111] grown transition metal oxide thin films and heterostructures, APL Materials, 2020, 8: 050904. 【Editor's Pick】
9. A. Arab, X. Liu, O. Koksal, W. Yang, R. U. Chandrasena, S. Middey, M. Kareev, S. Kumar, M.-A. Husanu, Z. Yang, L. Gu, V. N. Strocov, T.-L. Lee, J. Minar, R. Pentcheva, J. Chakhalian, A. X. Gray*, Electronic structure of a graphene-like artificial crystal of NdNiO₃, Nano Letters, 2019, 19(11): 8311-8317.
10. F. Wen*, X. Liu*, Q. Zhang, M. Kareev, B. Pal, Y. Cao, J. Freeland, A. T. N’Diaye, P. Shafer, E. Arenholz, L. Gu, J. Chakhalian, Interface-engineered hole doping in Sr₂IrO₄/LaNiO₃ heterostructures, New Journal of Physics, 2019, 21: 103009.
11. Y. Cao*, Z. Wang, S. Park, Y. Yuan, X. Liu, S. Nikitin, H. H. Akamatsu, M. Kareev, S. Middey, D. Meyers, P. Thompson, P. J. Ryan, P. Shafer, A. N’Diaye, E. Arenholz, V. Gopalan, Y. Zhu, K. Rabe, J. Chakhalian, Artificial two-dimensional polar metal at room temperature, Nature Communications, 2018, 9: 1547.
12. S. Middey*^#, D. Meyers*^#, M. Kareev, Y. Cao, X. Liu, P. Shafer, J. W. Freeland, J.-W. Kim, P. J. Ryan, J. Chakhalian, Disentangled cooperative orderings in artificial rare-earth nickelates, Physical Review Letters, 2018, 120: 156801.
13. X. Liu, Y. Cao, M. Kareev, S. Middey, J. Chakhalian*, Geometric engineering of complex oxide heterostructures: a novel approach to artificial quantum state, MRS Communications, 2016, 6: 133-144.
14. Y. Cao*, Z. Yang, M. Kareev, X. Liu, D. Meyers, S. Middey, D. Choudhury, P. Shafer, J. Guo, J. W. Freeland, E. Arenholz, L. Gu, J. Chakhalian, Magnetic interactions at the nanoscale in trilayer titanates, Physical Review Letters, 2016, 116: 076802.
15. S. Middey*, D. Meyers, D. Doennig, M. Kareev, X. Liu, Y. Cao, Z. Yang, J. Shi, L. Gu, P. J. Ryan, R. Pentcheva, J. W. Freeland, J. Chakalian, Mott electrons in an artificial graphenelike crystal of rare-earth nickelate, Physical Review Letters, 2016, 116: 056801.
16. Y. Cao*, X. Liu, M. Kareev, D. Choudhury. S. Middey, D. Meyers, J.-W. Kim, P. J. Ryan, J. W. Freeland, J. Chakhalian, Engineered Mott ground state in a LaTiO_3+δ/LaNiO₃ heterostructure, Nature Communications, 2016, 7: 10418.

        (* Corresponding author  # Equal contribution)

目前的研究课题及展望:

1. 探究新型氧化物拓扑材料薄膜的制备方法
2. 开发具有“多节点”的物态调控测试系统
3. 研究强关联拓扑材料薄膜的表面态与界面演生现象

培养研究生情况:

每年计划招收研究生1-2人，欢迎具有物理或材料背景的学生联系报考，也欢迎有兴趣和热情的本科生加入。在读学生有机会出国学习交流和访问。