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A Ferroptosis‐Inducing Arsenene‐Iridium Nanoplatform for Synergistic Immunotherapy in Pancreatic Cancer

2024-02-15T13:08:49+00:00February 15th, 2024|Categories: Publications|Tags: |

Due to multidrug resistance and the high risk of recurrence, effective and less toxic alternative pancreatic cancer treatments are urgently needed. Pancreatic cancer cells are highly resistant to apoptosis but sensitive to ferroptosis. In this study, an innovative nanoplatform (AsIr@PDA) was developed by electrostatic adsorption of a cationic iridium complex (IrFN) onto two-dimensional (2D) arsenene nanosheets. This nanoplatform exhibits superior ferroptosis-inducing effects with high drug loading capacity and, importantly, excellent anti-cancer immune activation function, leading to efficient elimination of pancreatic tumors with no observable side effects. Interestingly, AsIr@PDA significantly prevents the recurrence of pancreatic cancer in vivo when compared with cisplatin-loaded nanoplatform. This designed nanoplatform demonstrated superior therapeutic efficacy by synergistic ferroptosis-inducing chemotherapy with immunotherapy via an all-in-one strategy, providing new insights for future pancreatic cancer therapy.

Published in: "Angewandte Chemie International Edition".

Quantum Shot Noise Signatures of Two-Dimensional Semi-Dirac System. (arXiv:2303.04468v1 [cond-mat.mes-hall])

2023-03-09T04:30:24+00:00March 9th, 2023|Categories: Publications|Tags: , |

Two-dimensional ($2$D) semi-Dirac systems, such as $2$D black phosphorus and arsenene, can exhibit a rich topological phase transition between insulating, semi-Dirac, and band inversion phases when subjected to an external modulation. How these phase transitions manifest within the quantum transport and shot noise signatures remain an open question thus far. Here, we show that the Fano factor converges to the universal $Fapprox0.179$ at the semi-Dirac phase, and transits between the sub-Poissonian ($Fapprox1/3$) and the Poissonian shot noise ($Fapprox1$) limit at the band inversion and the insulating phase, respectively. Furthermore, the conductance of $2$D semi-Dirac system converges to the contrasting limit of $G/G_0 rightarrow 1/d$ and $G/G_0 rightarrow0$ at the band inversion and the insulating phases, respectively. The quantum tunneling spectra exhibits a peculiar coexistence of massless and massive Dirac quasiparticles in the band inversion regime, thus providing a versatile sandbox to study the tunneling behavior of various Dirac quasiparticles. These findings reveal the rich interplay between band topology and quantum transport signatures, which may serve as smoking gun signatures for the experimental studies of semi-Dirac systems near topological phase transition.

Published : "arXiv Mesoscale and Nanoscale Physics".

Uncovering the Structural Evolution Arsenene on SiC Substrate. (arXiv:2302.05475v1 [cond-mat.mtrl-sci])

2023-02-14T02:29:33+00:00February 14th, 2023|Categories: Publications|Tags: |

Two-dimensional arsenic allotropes have been grown on metallic surfaces, while topological properties have been theoretically described on strained structures. Here we experimentally grow arsenene by molecular beam epitaxy over the insulating SiC substrate. The arsenene presents a flat structure with a strain field that follows the SiC surface periodicity. Our ab initio simulations, based on the density functional theory, corroborate the experimental observation. The strained structure presents a new arsenene allotrope with a triangular structure, rather than the honeycomb previously predicted for other pnictogens. This strained structure presents a Peierls-like transition leading to an indirect gap semiconducting behavior.

Published in: "arXiv Material Science".

A First-Principles Study on the Adsorption of Small Molecules on Arsenene: Comparison of Oxidation Kinetics in Arsenene, Antimonene, Phosphorene and InSe. (arXiv:2203.12218v1 [cond-mat.mtrl-sci])

2022-03-24T02:29:34+00:00March 24th, 2022|Categories: Publications|Tags: , , , , |

Arsenene, a new group V two-dimensional (2D) semiconducting material beyond phosphorene and antimonene, has recently gained an increasing attention owning to its various interesting properties which can be altered or intentionally functionalized by chemical reactions with various molecules. This work provides a systematic study on the interactions of arsenene with the small molecules, including H2, NH3, O2, H2O, NO, and NO2. It is predicted that O2, H2O, NO, and NO2 are strong acceptors, while NH3 serves as a donor. Importantly, it is shown a negligible charge transfer between H2 and arsenene which is ten times lower than that between H2 and phosphorene and about thousand times lower than that between H2 and InSe and antimonene. The calculated energy barrier for O2 splitting on arsenene is found to be as low as 0.67 eV. Thus, pristine arsenene may easily oxidize in ambient conditions as other group V 2D materials. On the other hand, the acceptor role of H2O on arsenene, similarly to the cases of antimonene and InSe, may help to prevent the proton transfer between H2O and O species by forming acids, which suppresses further structural degradation of arsenene. The structural decomposition of the 2D layers upon interaction with the environment may be avoided due to the acceptor role of H2O molecules as the study predicts from the comparison of common group V 2D materials. However, the protection for arsenene is still required due to its strong interaction with other small environmental molecules. The present work renders the possible ways

Published in: "arXiv Material Science".

Second Order Topological Insulator State in Hexagonal Lattices and its Abundant Material Candidates. (arXiv:2108.09511v1 [cond-mat.mes-hall])

2021-08-24T02:30:15+00:00August 24th, 2021|Categories: Publications|Tags: , , , |

We propose two mechanisms to realize the second order topological insulator (SOTI) state in spinless hexagonal lattices, viz., chemical modification and anti-Kekul’e/Kekul’e distortion of hexagonal lattice. Correspondingly, we construct two models and demonstrate the nontrivial band topology of the SOTI state characterized by the second Stiefel-Whitney class $w_2$ in the presence of inversion symmetry ($textit{P}$) and time-reversal symmetry ($textit{T}$). Based on the two mechanisms and using first-principles calculations and symmetry analysis, we predict three categories of real light element material candidates, i.e., hydrogenated and halogenated 2D hexagonal group IV materials XY (X=C, Si, Ge, Sn, Y=H, F, Cl), 2D hexagonal group V materials (blue phosphorene, blue arsenene, and black phosphorene, black arsenene), and the recent experimentally synthesized anti-Kekul’e/Kekul’e order graphenes and the counterparts of silicene/germanene/stanene. We explicitly demonstrate the nontrivial topological invariants and existence of the protected corner states with fractional charge for these candidates with giant bulk band gap (up to 3.5 eV), which could facilitate the experimental verification by STM. Our approaches and proposed abundant real material candidates will greatly enrich 2D SOTIs and promote their intriguing physics research.

Published in: "arXiv Material Science".

Localized Wannier function based tight-binding models for two-dimensional allotropes of bismuth. (arXiv:2102.11486v1 [cond-mat.mtrl-sci])

2021-02-24T02:29:21+00:00February 24th, 2021|Categories: Publications|Tags: , |

With its monoelemental composition, various crystalline forms and an inherently strong spin-orbit coupling, bismuth has been regarded as an ideal prototype material to expand our understanding of topological electronic structures. In particular, two-dimensional bismuth thin films have attracted a growing interest due to potential applications in topological transistors and spintronics. This calls for an effective physical model to give an accurate interpretation of the novel topological phenomena shown by two-dimensional bismuth. However, the conventional semi-empirical approach of adapting bulk bismuth hoppings fails to capture the topological features of two-dimensional bismuth allotropes because the electronic band topology is heavily influenced by crystalline symmetries as well as atom spacings. Here we provide a new parameterization using localized Wannier functions derived from the Bloch states in first-principles calculations. We construct new tight-binding models for three types of two-dimensional bismuth allotropes: a Bi (111) bilayer, bismuthene and a Bi(110) bilayer. We demonstrate that our tight-binding models can successfully reproduce the band structures, symmetries and topological features of these two-dimensional allotropes. We anticipate that these models can be extended to other similar two-dimensional topological structures such as antimonene and arsenene. Moreover, these models can serve as a starting point for investigating the electron/spin transport and electromagnetic response in low-dimensional topological devices.

Published in: "arXiv Material Science".

Dissipative Transport and Phonon Scattering Suppression via Valley Engineering in Single-Layer Antimonene and Arsenene Field-Effect Transistors. (arXiv:2101.08392v1 [cond-mat.mes-hall])

2021-01-22T04:30:31+00:00January 22nd, 2021|Categories: Publications|Tags: , |

Two-dimensional (2D) semiconductors are promising channel materials for next-generation field-effect transistors (FETs) thanks to their unique mechanical properties and enhanced electrostatic control. However, the performance of these devices can be strongly limited by the scattering processes between carriers and phonons, usually occurring at high rates in 2D materials. Here, we use quantum transport simulations calibrated on first-principle computations to report on dissipative transport in antimonene and arsenene $n$-type FETs at the scaling limit. We show that the widely-used approximations of either ballistic transport or simple acoustic deformation potential scattering result in large overestimation of the ON current, due to neglecting the dominant intervalley and optical phonon scattering processes. We also propose a strategy to improve the device performance by removing the valley degeneracy and suppressing most of the intervalley scattering channels via an uniaxial strain along the zigzag direction. The method is applicable to other similar 2D semiconductors characterized by multivalley transport.

Published : "arXiv Mesoscale and Nanoscale Physics".

Band alignment of monolayer CaP$_3$, CaAs$_3$, BaAs$_3$ and the role of $p$-$d$ orbital interactions in the formation of conduction band minima. (arXiv:2012.02318v1 [cond-mat.mtrl-sci])

2020-12-07T02:29:31+00:00December 7th, 2020|Categories: Publications|Tags: , |

Recently, a number of new two-dimensional (2D) materials based on puckered phosphorene and arsenene have been predicted with moderate band gaps, good absorption properties and carrier mobilities superior to transition metal dichalcogenides. For heterojunction applications, it is important to know the relative band alignment of these new 2D materials. We report the band alignment of puckered CaP$_3$, CaAs$_3$ and BaAs$_3$ monolayers at the quasiparticle level of theory (G$_0$W$_0$), calculating band offsets for isolated monolayers according to the electron affinity rule. Our calculations suggest that monolayer CaP$_3$, CaAs$_3$ and BaAs$_3$ all form type-II (staggered) heterojunctions. Their quasiparticle gaps are 2.1 (direct), 1.8 (direct) and 1.5 eV (indirect), respectively. We also examine trends in the electronic structure in the light of chemical bonding analysis. We show that the indirect band gap in monolayer BaAs$_3$ is caused by relatively strong As $3p$ – Ba $5d$ bonding interactions that stabilize the conduction band away from the $Gamma$ point between $Gamma$ and $S$.

Published in: "arXiv Material Science".

Pentaoctite phase: A new group V allotrope. (arXiv:2008.12655v1 [cond-mat.mtrl-sci])

2020-08-31T02:29:36+00:00August 31st, 2020|Categories: Publications|Tags: , , |

By performing firt-principles electronic calculations we propose new a phase of group-V allotropes of antimonene, arsenene and phosphorene in the pentaoctite structure. By calculating the phonon spectra, we show that all these phases are stable. Whereas these structures have a indirect band gap, they can be made direct gap materials by applying external strain. GW calculations of the dielectric function demonstrate that all these structures have an absorption spectrum in the visible region, which could be useful for group-V optoelectronics.

Published in: "arXiv Material Science".

Blue phosphorene bilayer is a two-dimensional metal — and an unambiguous classification scheme for buckled hexagonal bilayers. (arXiv:2007.11027v1 [cond-mat.mtrl-sci])

2020-07-23T02:29:25+00:00July 23rd, 2020|Categories: Publications|Tags: , |

High-level first-principles computations predict blue phosphorene bilayer to be a two-dimensional metal. This structure has not been considered before and was identified by employing a block-diagram scheme that yields the complete set of five high-symmetry stacking configurations of buckled honeycomb layers, and allows their unambiguous classification. We show that all of these stacking configurations are stable or at least metastable configurations both for blue phosphorene and gray arsenene bilayers. For blue phosphorene, the most stable stacking configuration has not yet been reported, and surprisingly it is metallic, while all other arrangements are indirect band gap semiconductors. As it is impossible to interchange the stacking configurations by translations, all of them should be experimentally accessible via the transfer of monolayers. The metallic character of blue phosphorene bilayer is caused by its short interlayer distance of 3.01 {AA} and offers the exceptional possibility to design single elemental all-phosphorus transistors.

Published in: "arXiv Material Science".

Arsenene: A Potential Therapeutic Agent for Acute Promyelocytic Leukaemia Cells by Acting on Nuclear Proteins

2020-03-17T13:07:43+00:00March 17th, 2020|Categories: Publications|Tags: |

Course of action: Arsenene nanosheets have been shown to have potent antiproliferative activity against a variety of cancer cells, especially NB4 acute promyelocytic leukaemia cells, while showing no toxicity towards normal cells. A mechanistic study in NB4 cells revealed that arsenene induced the production of reactive oxygen species (ROS) and the depolarization of mitochondrial membrane potentials, thereby leading to apoptosis of the cells. Abstract Arsenene has recently emerged as a promising new two‐dimensional material for biomedical applications because of its excellent optical and electronic properties. Herein, novel 2D arsenene nanosheets were synthesized and shown to be effective against NB4 promyelocytic leukaemia (APL) cells (82 % inhibition) as well as inducing apoptosis while showing no toxicity towards normal cells. The high zeta potential, small size, and the planar structure were crucial to the toxicity of the materials. Label‐free proteomic profiling analysis suggested that arsenene affected nuclear DNA replication, nucleotide excision repair, and pyrimidine metabolism pathways by downregulating the DNA polymerases POLE, POLD1, POLD2, and POLD3. Mass spectrometric studies showed that arsenene bound mainly to nuclear nucleotide acid binding proteins in NB4 cells and further cellular fluorescence studies revealed that the arsenene destroyed the nuclei. In vivo toxicity tests in mice also indicated the physiological biosafety of arsenene.

Published in: "Angewandte Chemie International Edition".

Spin-orbit coupling in elemental two-dimensional materials

2019-09-16T14:38:07+00:00September 16th, 2019|Categories: Publications|Tags: , , , , , |

Author(s): Marcin Kurpas, Paulo E. Faria Junior, Martin Gmitra, and Jaroslav FabianThe fundamental spin-orbit coupling and spin mixing in graphene and rippled honeycomb lattice materials silicene, germanene, stanene, blue phosphorene, arsenene, antimonene, and bismuthene is investigated from first principles. The intrinsic spin-orbit coupling in graphene is revisited using multiba…[Phys. Rev. B 100, 125422] Published Mon Sep 16, 2019

Published in: "Physical Review B".

2D V‐V Binary Materials: Status and Challenges

2019-08-02T08:42:33+00:00August 2nd, 2019|Categories: Publications|Tags: , , , |

2D V‐V binary materials, as the internal combination of group‐VA elements (N, P, As, Sb, Bi), have become a popular research topic. Through the interaction among charge, orbital, lattice, and spin degrees of freedom, the favorable and superior properties in 2D V‐V binary materials can be further modulated, extending their application in novel electronic, optoelectronic, and energy devices. Abstract 2D phosphorene, arsenene, antimonene, and bismuthene, as a fast‐growing family of 2D monoelemental materials, have attracted enormous interest in the scientific community owing to their intriguing structures and extraordinary electronic properties. Tuning the monoelemental crystals into bielemental ones between group‐VA elements is able to preserve their advantages of unique structures, modulate their properties, and further expand their multifunctional applications. Herein, a review of the historical work is provided for both theoretical predictions and experimental advances of 2D V‐V binary materials. Their various intriguing electronic properties are discussed, including band structure, carrier mobility, Rashba effect, and topological state. An emphasis is also given to their progress in fabricated approaches and potential applications. Finally, a detailed presentation on the opportunities and challenges in the future development of 2D V‐V binary materials is given.

Published in: "Advanced Materials".

Spin-orbit coupling in elemental two-dimensional materials. (arXiv:1907.05152v1 [cond-mat.mes-hall])

2019-07-12T08:31:30+00:00July 12th, 2019|Categories: Publications|Tags: , , , , , , |

The fundamental spin-orbit coupling and spin mixing in graphene and rippled honeycomb lattice materials silicene, germanene, stanene, blue phosphorene, arsenene, antimonene, and bismuthene is investigated from first principles. The intrinsic spin-orbit coupling in graphene is revisited using multi-band $kcdot p$ theory, showing the presence of non-zero spin mixing in graphene despite the mirror symmetry. However, the spin mixing itself does not lead to the the Elliott-Yafet spin relaxation mechanism, unless the mirror symmetry is broken by external factors. For other aforementioned elemental materials we present the spin-orbit splittings at relevant symmetry points, as well as the spin admixture $b^2$ as a function of energy close to the band extrema or Fermi levels. We find that spin-orbit coupling scales as the square of the atomic number Z, as expected for valence electrons in atoms. For isolated bands, it is found that $b^2sim Z^4$. The spin-mixing parameter also exhibits giant anisotropy which, to a large extent, can be controlled by tuning the Fermi level. Our results for $b^2$ can be directly transferred to spin relaxation time due to the Elliott-Yafet mechanism, and therefore provide an estimate of the upper limit for spin lifetimes in materials with space inversion center.

Published : "arXiv Mesoscale and Nanoscale Physics".

Effect of Stone–Wales defects and transition-metal dopants on arsenene: a DFT study

2019-06-17T12:55:19+00:00June 17th, 2019|Categories: Publications|Tags: |

RSC Adv., 2019, 9,19048-19056DOI: 10.1039/C9RA03721G, Paper Open Access &nbsp This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence.Jialin Li, Qingxiao Zhou, Weiwei Ju, Qian Zhang, Yanling LiuThe structural, electronic, and magnetic properties of 3d transition metal (TM) atom (Sc, V,

Published in: "RSC Advances".

Interlayer decoupling in twisted bilayers of $beta$-phosphorus and arsenic: a computational study. (arXiv:1905.05951v1 [cond-mat.mtrl-sci])

2019-05-16T02:29:49+00:00May 16th, 2019|Categories: Publications|Tags: , |

We investigate magnetism and band structure engineering in Moir’e superlattice of blue phosphorus ($beta$-P) and grey arsenene ($beta$-As) bilayers, using textit{ab initio} calculations. The electronic states near the valence and conduction band edges have significant $p_z$ character in both the bilayers. Thus, twisting the layers significantly reduce the interlayer orbital overlap, leading to a decrease in the binding energy (up to $sim33%$) and an increase in interlayer distance (up to $sim10%$), compared to the most stable AA-stacking. This interlayer decoupling also results in a notable increase (up to $sim$25-50%) of the bandgap of twisted bilayers, with the valance band edge becoming relatively flat with van-Hove singularities in the density of states. Thus, hole doping induces a Stoner instability, leading to ferromagnetic ground state, which is more robust in Moir’e superlattices, than that of AA-stacked $beta$-P and $beta$-As.

Published in: "arXiv Material Science".

Tunable gap in stable arsenene nanoribbons opens the door to electronic applications

2019-04-16T16:32:26+00:00April 16th, 2019|Categories: Publications|Tags: |

RSC Adv., 2019, 9,11818-11823DOI: 10.1039/C9RA00975B, Paper Open Access &nbsp This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence.A. García-Fuente, J. Carrete, A. Vega, L. J. GallegoOur study of arsenene nanorribons uncovers their structural diversity and, more crucially, the tunability of

Published in: "RSC Advances".

Valley-engineering mobilities in 2D materials. (arXiv:1902.11209v1 [cond-mat.mtrl-sci])

2019-03-01T02:29:40+00:00March 1st, 2019|Categories: Publications|Tags: , , |

Two-dimensional materials are emerging as a promising platform for ultrathin channels in field-effect transistors. To this aim, novel high-mobility semiconductors need to be found or engineered. While extrinsic mechanisms can in general be minimized by improving fabrication processes, the suppression of intrinsic scattering (driven e.g. by electron-phonon interactions) requires to modify the electronic or vibrational properties of the material. Since intervalley scattering critically affects mobilities, a powerful approach to enhance transport performance relies on engineering the valley structure. We argue here how uniaxial strain can lift degeneracies and completely suppress scattering into entire valleys, dramatically improving performance. This is shown in detail for arsenene, where a 2% strain blocks scattering into 4 of the 6 valleys, and leads to a 600% increase in mobility. The mechanism is general and applies to other materials, including in particular the isostructural antimonene and blue phosphorene.

Published in: "arXiv Material Science".

Atomically Thin 2D‐Arsenene by Liquid‐Phased Exfoliation: Toward Selective Vapor Sensing

2019-02-02T22:32:35+00:00February 2nd, 2019|Categories: Publications|Tags: , , |

A liquid‐phase exfoliation procedure to prepare 2D‐arsenene via sonication is reported, and the formation of high‐quality few‐layer arsenene nanosheets with large lateral dimensions is confirmed. A vapor sensing using arsenene nanosheets is demonstrated, which can selectively detect methanol or acetone vapors depending on the selected resonance frequency. The results are highly reproducible, and the sensor has long‐term stability. Abstract Phosphorene and antimonene, single‐ or few‐layered (FL) semiconductor materials, have recently attracted enormous attention due to their unique properties, provided by their extreme thinness. Here, a liquid‐phase exfoliation (LPE) procedure to prepare FL arsenene, another member of pnictogens, assisted by sonication and without any additional surfactant is reported. The exfoliation process is performed in various solvents. Among those, N‐methylpyrrolidone is found to provide the highest concentration of stable arsenene sheets. Spectroscopic and microscopic analyses confirm the formation of high‐quality few‐layer arsenene nanosheets with large lateral dimensions. An application of this material for construction of vapor sensor based on electrochemical impedance spectroscopy is demonstrated. The device detects selectively methanol or acetone vapors depending on the selected resonance frequency. The results are highly reproducible, and the vapor sensor has long‐term stability.

Published in: "Advanced Functional Materials".

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