We demonstrate a machine learning-based approach which predicts the properties of crystal structures following relaxation based on the unrelaxed structure. Use of crystal graph singular values reduces the number of features required to describe a crystal by more than an order of magnitude compared to the full crystal graph representation. We construct machine learning models using the crystal graph singular value representations in order to predict the volume, enthalpy per atom, and metal versus semiconducting phase of DFT-relaxed organic salt crystals based on randomly generated unrelaxed crystal structures. Initial base models are trained to relate 89,949 randomly generated structures of salts formed by varying ratios of 1,3,5-triazine and HCl with the corresponding volumes, enthalpies per atom, and phase of the DFT-relaxed structures. We further demonstrate that the base model is able to extrapolate to new chemical systems with the inclusion of 2,000 to 10,000 crystal structures from the new system. After training a single model with a large number of data points, extension can be done at significantly lower cost. The constructed machine learning models can be used to rapidly screen large sets of randomly generated organic salt crystal structures and efficiently downselect the structures most likely to be experimentally realizable. The models can be used either as a stand-alone crystal structure predictor or incorporated into more sophisticated workflows as a filtering step.
Pressure-Induced Zero-Gap Semiconducting State in Organic Conductor $α$-(BEDT-TTF)$_2$I$_3$ Salt
我们显示了准二维有机导体$α$ -（BEDT-TTF）$_2$ I $_3$盐中的零能隙半导体（ZGS）态，其在沿a轴（BEDT-TTF分子的堆叠轴）的单轴压力下出现。ZGS状态是在费米点周围存在具有线性色散的带谱的狄拉克锥的状态，该狄拉克锥连接未被占据的（电子）带和被占据的（空穴）带。频谱表现出很大的各向异性的速度，这取决于从费米点的方向。通过改变一个紧束缚模型的几个转移能的大小与四个网站每个晶胞，它表明，ZGS状态存在于一个很宽的压力范围内，并归因于大的各向异性的转移能沿堆叠轴。
Floquet theory of photoinduced topological phase transitions in the organic salt $α$-(BEDT-TTF)$_2$I$_3$ irradiated with elliptically polarized light
本文从理论上研究了在单轴压力下有机盐$α$ -（BEDT-TTF）$_2$ I $_3$中可能发生的光致拓扑相变。Floquet分析的驱动紧束缚模型，这种材料揭示了丰富的光致变化的能带结构，陈数，霍尔电导率照射下的椭圆偏振光。所得到的相图包含多种非平衡稳定相，例如，Floquet Chern绝缘子、Floquet半金属和Floquet正常绝缘子相。这一工作拓宽了光致拓扑相变研究的目标材料范围，并有助于物质中电子态的光学操纵研究的发展。
Structural and electronic properties of $α,β$-(BEDT-TTF)$_2$I$_3$ and $κ$-(BEDT-TTF)$_2$X$_3$ (X=I,F,Br,Cl) organic charge transfer salts
（BEDT-TFF）$_2$ I $_3$电荷转移盐具有超导电性和压力诱导的准二维狄拉克锥。在密度泛函理论的框架下，采用从头计算方法研究了三种结构相$α$、$β$和$κ$的结构和电子性质. \edit{We furthermore report about the irreducible representations of the corresponding electronic band structures, symmetry of their crystal structure, and discuss the origin of band crossings. Additionally, we discuss the chemically induced strain in $κ$-(BEDT-TTF)$_2$I$_3$ achieved by replacing the Iodine layer with other Halogens: Fluorine, Bromine and Chlorine. In the case of $κ$-(BEDT-TTF)$_2$F$_3$, we identify topologically protected crossings within the band structure. These crossings are forc…
Organic ferroelectric Croconic Acid: A concise survey from bulk single crystals to thin films
有机铁电材料具有节能、环保等优点，是无机铁电材料的重要替代品。虽然第一个发现的铁电体，罗谢尔盐，是一种有机化合物的盐，有机铁电体并不像无机铁电体那样丰富。此外，迄今为止发现的有机系统中的小偏振值已经成为其应用的一个不利因素。然而，围绕这些材料的科学兴趣和活动，为了基本的理解和实际应用的目的，最近已经显着上升，特别是在发现克酮酸（4，5-二羟基-4-环戊烯-1，2，3-三酮，H2 C5 O 5）晶体中的超室温铁电性之后，其极化值与无机铁电体中发现的极化值相媲美。其大极化、有机性质和真空升华性使克酮酸成为无毒和无铅器件应用的理想候选物。在这篇评论文章中，我们调查的科学活动进行到目前为止，涉及铁电性在这种新型材料，同等重视其散装单晶和薄膜形式。在讨论铁电有序的起源和体材料中极化反转现象的同时，我们也总结了这种薄膜的应用方向。
Air-Water Interface-Assisted Synthesis and Charge Transport Characterization of Quasi-2D Polyacetylene Films with Enhanced Electron Mobility via Ring-Opening Polymerization of Pyrrole
