scholarly journals An electron-counting rule to determine the interlayer magnetic coupling of the van der Waals materials

2D Materials ◽  
2020 ◽  
Vol 7 (4) ◽  
pp. 045010 ◽  
Author(s):  
Jiewen Xiao ◽  
Binghai Yan
2020 ◽  
Vol 6 (30) ◽  
pp. eabb9379 ◽  
Author(s):  
Thomas A. Tartaglia ◽  
Joseph N. Tang ◽  
Jose L. Lado ◽  
Faranak Bahrami ◽  
Mykola Abramchuk ◽  
...  

Van der Waals (VdW) materials have opened new directions in the study of low dimensional magnetism. A largely unexplored arena is the intrinsic tuning of VdW magnets toward new ground states. Chromium trihalides provided the first such example with a change of interlayer magnetic coupling emerging upon exfoliation. Here, we take a different approach to engineer previously unknown ground states, not by exfoliation, but by tuning the spin-orbit coupling (SOC) of the nonmagnetic ligand atoms (Cl, Br, I). We synthesize a three-halide series, CrCl3 − x − yBrxIy, and map their magnetic properties as a function of Cl, Br, and I content. The resulting triangular phase diagrams unveil a frustrated regime near CrCl3. First-principles calculations confirm that the frustration is driven by a competition between the chromium and halide SOCs. Furthermore, we reveal a field-induced change of interlayer coupling in the bulk of CrCl3 − x − yBrxIy crystals at the same field as in the exfoliation experiments.


2021 ◽  
pp. 2102917
Author(s):  
Ruijin Sun ◽  
Shifeng Jin ◽  
Jun Deng ◽  
Munan Hao ◽  
Xin Zhong ◽  
...  

2021 ◽  
Vol 5 (1) ◽  
Author(s):  
Qianfan Nie ◽  
Caifang Gao ◽  
Feng-Shou Yang ◽  
Ko-Chun Lee ◽  
Che-Yi Lin ◽  
...  

AbstractRecently, researchers have focused on optoelectronics based on two-dimensional van der Waals materials to realize multifunctional memory and neuron applications. Layered indium selenide (InSe) semiconductors satisfy various requirements as photosensitive channel materials, and enable the realization of intriguing optoelectronic applications. Herein, we demonstrate InSe photonic devices with different trends of output currents rooted in the carrier capture/release events under various gate voltages. Furthermore, we reported an increasing/flattening/decreasing synaptic weight change index (∆Wn) via a modulated gate electric field, which we use to imitate medicine-acting metaplasticity with effective/stable/ineffective features analogous to the synaptic weight change in the nervous system of the human brain. Finally, we take advantage of the low-frequency noise (LFN) measurements and the energy-band explanation to verify the rationality of carrier capture-assisted optoelectronics applied to neural simulation at the device level. Utilizing optoelectronics to simulate essential biomedical neurobehaviors, we experimentally demonstrate the feasibility and meaningfulness of combining electronic engineering with biomedical neurology.


2021 ◽  
Author(s):  
Yan Liang ◽  
Shiying Shen ◽  
Baibiao Huang ◽  
Ying Dai ◽  
Yandong Ma

2D intercorrelated ferroelectrics, exhibiting a coupled in-plane and out-of-plane ferroelectricity, is a fundamental phenomenon in the field of condensed-mater physics. The current research is based on the paradigm of bi-directional...


Author(s):  
Yanxia Wang ◽  
Xue Jiang ◽  
Yi Wang ◽  
Jijun Zhao

Exploring two-dimensional (2D) ferromagnetic materials with intrinsic Dirac half-metallicity is crucial for the development of next-generation spintronic devices. Based on first-principles calculations, here we propose a simple valence electron-counting rule...


2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Chaowei Hu ◽  
Kyle N. Gordon ◽  
Pengfei Liu ◽  
Jinyu Liu ◽  
Xiaoqing Zhou ◽  
...  

AbstractMagnetic topological insulators (TI) provide an important material platform to explore quantum phenomena such as quantized anomalous Hall effect and Majorana modes, etc. Their successful material realization is thus essential for our fundamental understanding and potential technical revolutions. By realizing a bulk van der Waals material MnBi4Te7 with alternating septuple [MnBi2Te4] and quintuple [Bi2Te3] layers, we show that it is ferromagnetic in plane but antiferromagnetic along the c axis with an out-of-plane saturation field of ~0.22 T at 2 K. Our angle-resolved photoemission spectroscopy measurements and first-principles calculations further demonstrate that MnBi4Te7 is a Z2 antiferromagnetic TI with two types of surface states associated with the [MnBi2Te4] or [Bi2Te3] termination, respectively. Additionally, its superlattice nature may make various heterostructures of [MnBi2Te4] and [Bi2Te3] layers possible by exfoliation. Therefore, the low saturation field and the superlattice nature of MnBi4Te7 make it an ideal system to investigate rich emergent phenomena.


2021 ◽  
Author(s):  
Yani Zhang ◽  
Zhuo-ying Song ◽  
Dun Qiao ◽  
Xiaohui Li ◽  
Zhe Guang ◽  
...  

Abstract 2D van der Waals materials are crystals composed of atomic layers, which have atomic thickness scale layers and rich distinct properties, including ultrafast optical response, surface effects, light-mater interaction, small size effects, quantum effects and macro quantum tunnel effects. With the exploration of saturable absorption characteristic of 2D van der Waals materials, a series of potential applications of 2D van der Waals materials as high threshold, broadband and fast response saturable absorbers (SAs) in ultrafast photonics have been proposed and confirmed. Herein, the photoelectric characteristics, nonlinear characteristic measurement technique of 2D van der Waals materials and the preparation technology of SAs are systematically described. Furthermore, the ultrafast pulsed fiber lasers based on classical 2D van der Waals materials including graphene, Transition Metal Chalcogenides (TMCs), Topological Insulators (TIs) and Black Phosphorus (BP) have been fully summarized and analyzed. On this basis, opportunities and directions in this field, as well as the research results of ultrafast pulsed fiber lasers based on the latest 2D van der Waals materials (such as PbO, FePSe3, graphdiyne, bismuthene, Ag2S and MXene etc.), are reviewed and summarized.


Nanoscale ◽  
2019 ◽  
Vol 11 (30) ◽  
pp. 14113-14117 ◽  
Author(s):  
Mengfei Xue ◽  
Qi Zheng ◽  
Runkun Chen ◽  
Lihong Bao ◽  
Shixuan Du ◽  
...  

Near-field imaging of mid-infrared waveguide in SnSe2 slabs promotes two-dimensional van der Waals materials as building blocks for integrated MIR chips.


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