基于密度泛函理论（DFT）的计算方法，包括原位Hubbard $U$项，我们研究了衬底诱导应变对亚铁磁性Fe $_2$ O $_3$ -FeTiO $_3$固溶体和异质结构性质的影响.虽然通过形成混合的\fetw、\feth -接触层的电荷补偿机制不受影响，但应变可用于调节系统的电子性质，例如通过改变带隙中杂质能级的位置。与Fe $_{2}$ O $_{3}$（0001）或FeTiO $_{3}$（0001）-衬底上的膜相比，发现在通常用作衬底的Al $_{2}$ O $_{3}$（0001）的横向参数下的应变赤铁矿/钛铁矿膜在能量上是不利的。
英文摘要：
Based on density functional theory (DFT) calculations including an on-site Hubbard $U$ term we investigate the effect of substrate-induced strain on the properties of ferrimagnetic Fe$_2$O$_3$-FeTiO$_3$ solid solutions and heterostructures. While the charge compensation mechanism through formation of a mixed \fetw, \feth-contact layer is unaffected, strain can be used to tune the electronic properties of the system, e.g. by changing the position of impurity levels in the band gap. Straining hematite/ilmenite films at the lateral parameters of Al$_{2}$O$_{3}$(0001), commonly used as a substrate, is found to be energetically unfavorable as compared to films on Fe$_{2}$O$_{3}$(0001) or FeTiO$_{3}$(0001)-substrates.
A Comparative Study on Spin-Orbit Torque Efficiencies from W/ferromagnetic and W/ferrimagnetic Heterostructures
它已被证明，W在其电阻形式具有最大的自旋霍尔比在所有重过渡金属，这使得它是一个很好的候选人产生有效的阻尼类自旋轨道扭矩（DL-SOT）作用于相邻的铁磁或亚铁磁（FM）层。在这里，我们提供了一个系统的研究的自旋输运性质的W/FM磁性异质结构的FM层是铁磁Co $_{20}$ Fe $_{60}$ B $_{20}$或亚铁磁Co $_{63}$ Tb $_{37}$与垂直磁各向异性。采用电流诱导磁滞回线法研究了W/Co $_{20}$ Fe $_{60}$ B $_{20}$和W/Co $_{63}$ Tb $_{37}$体系的DL-SOT效率$|ξ_{DL}|$与W缓冲层的微观结构之间的关系。在W/Co $_{20}$ Fe $_{60}$ B $_{20}$和W/Co $_{63}$ Tb $_{37}$异质结构中，当W层部分非晶时，分别获得最大值的$|ξ_{DL}|\approx 0.144$和$|ξ_{DL}|\approx 0.116$。我们的研究结果表明，自旋霍尔效应从电阻相的W可以被用来有效地控制铁磁和亚铁磁层通过DL-SOT机制。
Exploring interfacial exchange coupling and sublattice effect in heavy metal/ferrimagnetic insulator heterostructures using Hall measurements, x-ray magnetic circular dichroism, and neutron reflectometry
Coupled spin dynamics in epitaxial trilayer heterostructures of ferrimagnetic garnet
Massachusetts Institute of Technology（麻省理工学院）；Politecnico di Milano（米兰理工大学）；Northeastern University（东北大学）；Brno University of Technology（布尔诺理工大学）；Heriot-Watt University（赫瑞瓦特大学）
Size dependent electric voltage-controlled magnetic anisotropy in multiferroic heterostructures: Interface-charge and strain co-mediated magnetoelectric coupling
Van der Waals heterostructures are constructed by stacking different atomic layers and can inherit many novel electronic and optical properties from the constituting atomic layers. Mechanical stability is of key importance for the high performance of nano devices based on the van der Waals heterostructure. In particular, buckling instability is a critical mechanical issue for the heterostructure due to its two-dimensional nature. Using graphene/MoS$_2$ heterostructure as an example, the present work demonstrates the relationship between the buckling instability and the inevitable misfit strain…
Electrical manipulation of magnetism via spin-orbit torques (SOTs) promises efficient spintronic devices. In systems comprising magnetic insulators and heavy metals, SOTs have started to be investigated only recently, especially in systems with interfacial Dzyaloshinskii-Moriya interaction (iDMI). Here, we quantitatively study the SOT efficiency and iDMI in a series of gadolinium gallium garnet (GGG) / thulium iron garnet (TmIG) / platinum (Pt) heterostructures with varying TmIG and Pt thicknesses. We find that the non-monotonic SOT efficiency as a function of the magnetic layer thickness is n…
Van der Waals heterostructures such as graphene/MoS$_2$ are promising candidates for plenty of optical or electronic applications, owing to advanced properties inherited from the constitutional atomic layers. Thermal expansion is an important phenomenon to be considered for the thermal stability of the van der Waals heterstructure as temperature commonly rises during the operation of nano devices. In the present work, the thermal expansion coefficient for the graphene/MoS$_2$ heterostructure is investigated by molecular dynamics simulations, and the effect from the unavoidable misfit strain on…
Compensation-Like Temperature and Spin-Flip Switch in Strained Thulium Iron Garnet Thin Films: Tuning Sublattice Interactions for Ferrimagnetic Spintronics
The compositional as well as structural asymmetries in Janus transition metal dichalcogenides (J-TMDs) and their van der Waals heterostructures (vdW HSs) induce an intrinsic Rashba spin-splitting. We investigate the variation of band-gaps and the Rashba parameter in three different Janus heterostructures having AB-stacked Mo$XY$/W$XY$ ($X$, $Y$ = S, Se, Te; $X\neq Y$) geometry with a $Y-Y$ interface, using first-principles calculations. We consider the effect of external electric field and in-plane biaxial strain in tuning the strength of the intrinsic electric field, which leads to remarkable…
Strain Modulated Electronic and Optical Properties of Laterally Stitched MoSi2N4/XSi2N4 (X=W, Ti) 2D Heterostructures
International Research Centre MagTop, Institute of Physics, Polish Academy of Sciences（波兰科学院物理研究所磁顶国际研究中心）；Department of Physics, Riphah International University, Campus Lahore（拉合尔校区里法赫国际大学物理系）；School of Materials Science and Engineering, CAPT, Peking University（北京大学CAPT材料科学与工程学院）；Department of Physics, University of Antwerp（安特卫普大学物理系）
The improved photocatalytic water splitting using 2D materials has technological importance for economically viable renewable energy. The present study focuses on the effect of uniaxial, biaxial, and vertical strain on the energy gap and band edge positions of C2N/MoS2 van der Waals heterostructures through first-principles density functional theory using PBE and SCAN functionals. The calculations establish that SCAN functional provides comparatively much better results as compared to the PBE for the band gap and band alignment study. The heterostructure exhibits a type- II band alignment whic…
The quasi-two-dimensional electronic gas at the (111) SrTiO$_3$-based heterostructure interfaces is described by a multi-band tight-binding model providing electronic bands in agreement at low energies with photoemission experiments. We analyze both the roles of the spin-orbit coupling and of the trigonal crystal field effects. We point out the presence of a regime with sizable strain where the band structure exhibits a Dirac cone whose features are consistent with \textit{ab-initio} approaches. The combined effect of spin-orbit coupling and trigonal strain gives rise to non-trivial spin and o…
Controlling magnetism by using electric fields is a goal of research towards novel spintronic devices and future nano-electronics. For this reason, multiferroic heterostructures attract much interest. Here we provide experimental evidence, and supporting DFT analysis, of a transition in La0.65Sr0.35MnO3 (LSMO) thin film to a stable ferromagnetic phase, that is induced by the structural and strain properties of the ferroelectric BaTiO3 (BTO) substrate, which can be modified by applying external electric fields. X-ray Magnetic Circular Dichroism (XMCD) measurements on Mn L edges with a synchrotr…
Strain and spin orbit coupling effects on electronic and optical properties of 2D CX/graphene (X = S, Se, Te) vdW heterostructure for solar energy harvesting
Van der Waals heterostructures (vdWHs) combine different layered materials with properties of interest,1 such as two-dimensional (2D) semimetals, semiconductors, magnets or superconductors. These heterostructures provide the possibility of engineering new materials with emergent functionalities that are not accessible in another way. Beyond inorganic 2D materials, layered molecular materials remain still rather unexplored, with only few examples regarding their isolation as atomically thin-layers. By a proper chemical design, the physical properties of these systems can be tuned, as illustrate…
Interface and Strain Control of Emergent Weyl Semimetallic Phase in SrNbO$_{3}$/LaFeO$_{3}$ Heterostructures
Institute of Physics, Bhubaneswar（布巴内斯瓦尔物理研究所）；Homi Bhabha National Institute（霍米·巴巴国立研究所）；Center for Atomistic Modelling and Materials Design, Indian Institute of Technology Madras（马德拉斯印度理工学院原子建模与材料设计中心）；Condensed Matter Theory and Computational Lab, Department of Physics, Indian Institute of Technology Madras（马德拉斯印度理工学院物理系凝聚态理论与计算实验室）；Laboratoire Albert Fert, CNRS, Thales, Université Paris-Saclay（阿尔伯特·费特实验室，法国国家科学研究中心，泰雷兹，巴黎萨克雷大学）；School of Basic Sciences, Indian Institute of Technology Bhubaneswar（布巴内斯瓦尔印度理工学院基础科学学院）；School of Physical Sciences, National Institute of Science Education and Research（国立科学教育与研究学院物理科学学院）；Peter Grünberg Institute, Forschungszentrum Jülich（于利希研究中心彼得·格林伯格研究所）；Department of Physics, Indian Institute of Science Bangalore（班加罗尔印度理工学院物理系）
We present a study of the control of electric field induced strain on the magnetic and electrical transport properties in a magneto-elastically coupled artificial multiferroic Fe3O4/BaTiO3 heterostructure. In this Fe3O4/BaTiO3 heterostructure, the Fe3O4 thin film is epitaxially grown in the form of bilateral domains, analogous to a-c stripe domains of the underlying BaTiO3(001) substrate. By in-situ electric field dependent magnetization measurements, we demonstrate the extrinsic control of the magnetic anisotropy and the characteristic Verwey metal-insulator transition of the epitaxial Fe3O4 …
Impact of misfit strain on the properties of tetragonal Pb(Zr,Ti)O3 thin film heterostructures
采用脉冲激光沉积法在SrTiO 3（100）衬底上制备了PbZr 0. 2 Ti 0. 8 O 3和PbZr 0. 4 Ti 0. 6 O 3异质结薄膜。利用铁电双层结构所提供的附加界面，通过改变层的排列顺序，可以改变位错含量和畴结构。通过透射电子显微镜研究了所得的微观结构。宏观铁电测量表明位错的形成和a/c畴结构对铁电极化和介电常数有很大的影响。的热力学分析使用的LANDAU-GINZBURG-DEVONSHIRE的方法，考虑到两个铁电层的厚度和静电耦合的比率被用来描述的实验数据。
Magnetic skyrmions $-$ localized chiral spin structures $-$ show great promise for spintronic applications. The recent discovery of two-dimensional (2D) magnetic materials opened new opportunities for exploring such topological spin structures in atomically thin van der Waals (vdW) materials. Despite recent progress in stabilizing metastable skyrmions in 2D magnets, their diameters are still beyond 100~nm and their lifetime, which is essential for applications, has not been explored yet. Here, using first-principles calculations and atomistic spin simulations, we predict that compressive mecha…
