Article
Materials Science, Multidisciplinary
Meryem Bouaziz, Wei Zhang, Yongfeng Tong, Hamid Oughaddou, Hanna Enriquez, Rym Mlika, Hafsa Korri-Youssoufi, Zhesheng Chen, Heqi Xiong, Yingchun Cheng, Azzedine Bendounan
Summary: In this study, the structural and electronic properties of Au(111) surface after Te deposition in ultrahigh vacuum were investigated. The results showed different surface reconstructions and potential formation of an Au-Te alloy structure at different Te film thicknesses.
Article
Chemistry, Multidisciplinary
Alessandro De Vita, Thao Thi Phuong Nguyen, Roberto Sant, Gian Marco Pierantozzi, Danila Amoroso, Chiara Bigi, Vincent Polewczyk, Giovanni Vinai, Loi T. Nguyen, Tai Kong, Jun Fujii, Ivana Vobornik, Nicholas B. Brookes, Giorgio Rossi, Robert J. Cava, Federico Mazzola, Kunihiko Yamauchi, Silvia Picozzi, Giancarlo Panaccione
Summary: This research investigates the ground state electronic properties of CrI3 and VI3 and reveals the stability of different electronic phases and the influence of dimensionality effects.
Article
Chemistry, Physical
Kangli Wang, Thomas Vincent, Jean Baptiste Bouhiron, Stephane Pons, Dimitri Roditchev, Sabina Simon, Mikhail Fonin, Beate Paulus, Yuriy Dedkov, Sergio Vlaic, Elena Voloshina
Summary: The interaction strength between graphene and substrate is strongly affected by the composition and nature of an alloy, leading to significant differences in the electronic structure of monolayer graphene on different Co-Ir alloys. This is supported by ARPES data showing the disappearance and restoration of the Dirac cone under different conditions.
Article
Chemistry, Multidisciplinary
Florian Margot, Simone Lisi, Irene Cucchi, Edoardo Cappelli, Andrew Hunter, Ignacio Gutierrez-Lezama, KeYuan Ma, Fabian von Rohr, Christophe Berthod, Francesco Petocchi, Samuel Ponce, Nicola Marzari, Marco Gibertini, Anna Tamai, Alberto F. Morpurgo, Felix Baumberger
Summary: In this study, the electronic structure of 2-9 layer black phosphorus (BP) was determined by using a newly developed laser-based microfocus angle resolved photoemission (μ-ARPES) system. The results reveal ladder-like anisotropic, quantized subbands that deviate from the scaling observed in conventional semiconductor quantum wells. In addition, universal tight-binding parameters were determined to accurately describe the electronic structure for all thicknesses.
Article
Chemistry, Physical
Stephan Appelfeller, Martin Franz, Murat Karadag, Milan Kubicki, Robert Zielinski, Maxim Krivenkov, Andrei Varykhalov, Alexei Preobrajenski, Mario Daehne
Summary: The terbium-induced nanostructures and their growth on Si(110) were comprehensively characterized using various techniques. It was found that a wetting layer formed at low terbium coverage, which gradually decreased with increasing coverage to give rise to unidirectional terbium silicide nanowires. These nanowires exhibited high aspect ratios at high annealing temperatures or on substrates containing terbium. The wetting layer and nanowires were both stable at temperatures up to 750 degrees C. In contrast to the nanowires, the wetting layer had a band gap, resulting in the semiconducting surrounding that insulated the nanowires.
APPLIED SURFACE SCIENCE
(2023)
Article
Materials Science, Multidisciplinary
Junqiu Zhang, Xingxing Dong, Shaogang Xu, Yipu Xia, Wingkin Ho, Hu Xu, Maohai Xie
Summary: In this study, platinum-phosphorus networks were obtained by P adsorption on Pt(111), enriching the diverse structures of metal-phosphorus networks and providing new insights into the formation mechanism of epitaxial P and its interaction with the noble metal substrate.
Article
Materials Science, Multidisciplinary
Wang Xiyang, Hao Qunqing, Zhang Yun, Pan Qifa, Chen Qiuyun, Feng Wei, Wang Yonghuan, Zhu Xiegang, Luo Lizhu, Lai Xinchun, Liu Qin, Tan Shiyong
Summary: High-quality USb2 thin films were successfully prepared on graphene/6H-SiC(0001) surface by molecule beam epitaxy, exhibiting similar surface atomic structure, electric transport property and band structure to those of bulk USb2 single crystals.
RARE METAL MATERIALS AND ENGINEERING
(2022)
Article
Chemistry, Multidisciplinary
Dharmendra Pant, Sandip Aryal, Subhasish Mandal, Ranjit Pati
Summary: Researchers have revealed ferromagnetism in twisted bilayer graphene nanoflex using first-principles approach, finding that the ferromagnetic phase appears irregularly between 0 and 30 degrees, rather than only at specific “magic angles”. The origin of electronic instability is attributed to aperiodic modulation of interlayer interaction in the nanoflex, resulting in the breaking of several higher-symmetry phases to lower the energy.
Article
Nanoscience & Nanotechnology
Fuqiang Hua, Pengfei Lv, Min Hong, Sen Xie, Min Zhang, Cheng Zhang, Wei Wang, Zhaohui Wang, Yong Liu, Yonggao Yan, Shengjun Yuan, Wei Liu, Xinfeng Tang
Summary: This study visualizes the dominant native atomic defects in SnTe and clarifies an alternative optimization mechanism for the electronic transport properties through defect engineering. Increasing substrate temperature and adjusting the Te/Sn flux ratio during film growth can manipulate the hole density and carrier mobility in SnTe films, leading to an improved power factor. The findings contribute to a better understanding of the electronic transport properties in SnTe-based compounds.
ACS APPLIED MATERIALS & INTERFACES
(2021)
Article
Multidisciplinary Sciences
Emmanouil Frantzeskakis, Ji Dai, Cedric Bareille, Tobias C. Roedel, Monika Guettler, Sheng Ran, Noravee Kanchanavatee, Kevin Huang, Naveen Pouse, Christian T. Wolowiec, Emile D. L. Rienks, Pascal Lejay, Franck Fortuna, M. Brian Maple, Andres F. Santander-Syro
Summary: Spontaneous symmetry breaking leads to phase transitions characterized by an order parameter, with phase transitions involving unknown order parameters being rare but intriguing. The transition of the heavy fermion compound URu2Si2 into the hidden-order phase is still unsolved, with research showing the interaction between heavy fermions and conduction band states near the Fermi level playing a crucial role. Analysis using angle-resolved photoemission spectroscopy reveals that the nonrigid change in the electronic structure between the hidden-order and antiferromagnetic phases suggests a change in the interaction strength between states near the Fermi level is crucial for the phase transition.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Chemistry, Physical
Marcin Rosmus, Natalia Olszowska, Zbigniew Bukowski, Pawel Starowicz, Przemyslaw Piekarz, Andrzej Ptok
Summary: This paper conducts a complex analysis of the electronic band structure of LaAgSb2 using ARPES and theoretical studies, identifying nodal lines related to crystal symmetry and from the vanishing of spin-orbit splitting at the X-M-A-R plane.
Article
Physics, Condensed Matter
Yichen Yang, Hengzhe Lu, Jian Yuan, Zhengtai Liu, Zhicheng Jiang, Zhe Huang, Jianyang Ding, Jiayu Liu, Soohyun Cho, Jishan Liu, Zhonghao Liu, Yanfeng Guo, Yi Zheng, Dawei Shen
Summary: We report the low-energy electronic structure of KMnBi, a two-dimensional antiferromagnetic material, measured by angle-resolved photoemission spectroscopy. Electric transport measurement and other techniques are used to study the evolution of electric transport characteristics with varied flake thicknesses, which consistently reveal the existence of a probable antiferromagnetic ground state. The phase transition temperature ranges from 220 K to 275 K, depending on the thickness. Our results suggest that multilayer KMnBi is a promising 2D antiferromagnetic platform for device applications.
JOURNAL OF PHYSICS-CONDENSED MATTER
(2023)
Article
Chemistry, Physical
Marc G. Cuxart, Daniele Perilli, Sena Toemekce, Joel Deyerling, Felix Haag, Matthias Muntwiler, Francesco Allegretti, Cristiana Di Valentin, Willi Auwaerter
Summary: This work demonstrates how naturally occurring moire' patterns in Ir(111)-supported graphene can template the formation of ordered arrays of boron species. Experimental and theoretical studies provide a comprehensive understanding of the distribution, bonding configurations, interfacial interaction, and impact on graphene's electronic structure. The results show that boron prefers to form small aggregates by inducing local bending of graphene.
Article
Chemistry, Physical
Antonio J. Martinez-Galera, Haojie Guo, Mariano D. Jimenez-Sanchez, Enrique G. Michel, Jose M. Gomez-Rodriguez
Summary: New opportunities for graphene engineering can be achieved by adjusting interfacial interaction in terms of d-band filling and geometry of the support. Growth of graphene on Rh(110) surfaces shows distinct stripe-like moire patterns and Dirac cones around the Fermi level. The analysis also reveals the existence of two levels of interfacial interaction strength and the presence of Dirac cones in band structures of different rotational domains, indicating potential for novel graphene-metal interfaces.
Article
Multidisciplinary Sciences
John P. Perdew, Adrienn Ruzsinszky, Jianwei Sun, Niraj K. Nepal, Aaron D. Kaplan
Summary: Strong correlations within a symmetry-unbroken ground-state wavefunction may manifest in approximate density functional theory as symmetry-broken spin densities or total densities, arising from soft modes of fluctuations such as spin-density or charge-density waves. An approximate density functional that breaks symmetry can be more revealing than an exact functional that does not, with examples including the stretched H-2 molecule, antiferromagnetic solids, and the static charge-density wave/Wigner crystal phase of a low-density jellium. Time-dependent density functional theory quantitatively shows that the static charge-density wave is a soft plasmon, with the frequency of a related density fluctuation dropping to zero.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Chemistry, Physical
Stephan Appelfeller, Martin Franz, Murat Karadag, Milan Kubicki, Robert Zielinski, Maxim Krivenkov, Andrei Varykhalov, Alexei Preobrajenski, Mario Daehne
Summary: The terbium-induced nanostructures and their growth on Si(110) were comprehensively characterized using various techniques. It was found that a wetting layer formed at low terbium coverage, which gradually decreased with increasing coverage to give rise to unidirectional terbium silicide nanowires. These nanowires exhibited high aspect ratios at high annealing temperatures or on substrates containing terbium. The wetting layer and nanowires were both stable at temperatures up to 750 degrees C. In contrast to the nanowires, the wetting layer had a band gap, resulting in the semiconducting surrounding that insulated the nanowires.
APPLIED SURFACE SCIENCE
(2023)
Article
Physics, Multidisciplinary
Xian P. Yang, Yigui Zhong, Sougata Mardanya, Tyler A. Cochran, Ramakanta Chapai, Akifumi Mine, Junyi Zhang, Jaime Sanchez-Barriga, Zi-Jia Cheng, Oliver J. Clark, Jia-Xin Yin, Joann Blawaf, Guangming Cheng, Ilya Belopolski, Tsubaki Nagashima, Sahand Najafzadeh, Shiyuan Gao, Nan Yao, Arun Basrasil, Rongying Jin, Tay-Ron Chang, Shik Shin, Kozo Okazaki, M. Zahid Hasan
Summary: We investigate the momentum dependence of the superconducting gap distribution in the Dirac material PdTe, and find that it is a spin-orbit coupled Dirac semimetal with a topological Fermi arc. The surface state of PdTe exhibits a fully gapped superconducting Cooper pairing structure below Tc (approximately 4.5 K), while a node is observed in the bulk near the Brillouin zone boundary, away from the topological Fermi arc. These observations demonstrate the band resolved electronic correlation between topological Fermi arc states and their role in Cooper pairing, as well as the coexistence of nodeless and nodal gap structures enforced by spin-orbit coupling in PdTe.
PHYSICAL REVIEW LETTERS
(2023)
Article
Instruments & Instrumentation
Yuran Niu, Nikolay Vinogradov, Alexei Preobrajenski, Claudia Struzzi, Brice Sarpi, Lin Zhu, Evangelos Golias, Alexei Zakharov
Summary: MAXPEEM is a dedicated photoemission electron microscopy beamline at MAX IV Laboratory, featuring an aberration-corrected spectroscopic photoemission and low-energy electron microscope (AC-SPELEEM). This powerful instrument offers a wide range of complementary techniques with a single-digit nanometer spatial resolution for structure, chemistry, and magnetic sensitivities. The beamline can deliver a high photon flux of >= 10(15) photons s(-1) (0.1% bandwidth)(-1) in the range 30-1200 eV, with full control of polarization.
JOURNAL OF SYNCHROTRON RADIATION
(2023)
Article
Chemistry, Physical
Nadezhda V. Vladimirova, Alexander S. Frolov, Jaime Sanchez-Barriga, Oliver J. Clark, Fumihiko Matsui, Dmitry Yu Usachov, Matthias Muntwiler, Carolien Callaert, Joke Hadermann, Vera S. Neudachina, Marina E. Tamm, Lada Yashina
Summary: Occupancy of different structural positions in a crystal lattice plays a key role in material properties. X-ray Photoelectron Diffraction (XPD) is a surface science structural method that can be used for occupancy analysis. By studying Sb2(Te1-xSex)3 mixed crystals, we found that XPD data showed excellent agreement with the reference method. We also discovered significant differences in anion occupancy between the surface and bulk.
SURFACES AND INTERFACES
(2023)
Article
Chemistry, Multidisciplinary
Matteo Jugovac, Iulia Cojocariu, Jaime Sanchez-Barriga, Pierluigi Gargiani, Manuel Valvidares, Vitaliy Feyer, Stefan Bluegel, Gustav Bihlmayer, Paolo Perna
Summary: By europium doping, single spin-polarized bands can be generated in monolayer graphene supported by the Co(0001) surface. The doping is controlled by Eu positioning, allowing for the formation of a K over bar $\bar{\mathrm{K}}$-valley localized single spin-polarized low-dispersive parabolic band close to the Fermi energy when Eu is on top, and of a & pi;* flat band with single spin character when Eu is intercalated underneath graphene. In the latter case, Eu also induces a bandgap opening at the Dirac point while the Eu 4f states act as a spin filter, splitting the & pi; band into two spin-polarized branches. The generation of flat bands with single spin character, as revealed by the spin- and angle-resolved photoemission spectroscopy (ARPES) experiments, complemented by density functional theory (DFT) calculations, opens up new pathways toward the realization of spintronic devices exploiting such novel exotic electronic and magnetic states.
ADVANCED MATERIALS
(2023)
Article
Physics, Multidisciplinary
J. Sanchez-Barriga, O. J. Clark, M. G. Vergniory, M. Krivenkov, A. Varykhalov, O. Rader, L. M. Schoop
Summary: In this study, the electronic structure of Au2Pb is investigated using angle-resolved photoemission spectroscopy. It is found that Au2Pb exhibits the characteristics of a three-dimensional Dirac semimetal, with the bulk Dirac cone structure undergoing a significant downward shift in binding energy as the temperature decreases, eventually undergoing a Lifshitz transition. These findings not only expand the range of known materials exhibiting three-dimensional Dirac phases, but also demonstrate a possible mechanism for controlling the contribution of the degeneracy point to electron transport without external doping.
PHYSICAL REVIEW LETTERS
(2023)
Article
Physics, Multidisciplinary
Tyler A. Cochran, Ilya Belopolski, Kaustuv Manna, Mohammad Yahyavi, Liu Yiyuan, Daniel S. Sanchez, Cheng Zi-Jia, Xian P. Yang, Daniel Multer, Yin Jia-Xin, Horst Borrmann, Alla Chikina, Jonas A. Krieger, Jaime Sanchez-Barriga, Patrick Le Fevre, Francois Bertran, Vladimir N. Strocov, Jonathan D. Denlinger, Chang Tay-Rong, Jia Shuang, Claudia Felser, Hsin Lin, Chang Guoqing, M. Zahid Hasan
Summary: In this Letter, the authors discovered the higher-fold topology of a chiral crystal using a combination of fine-tuned chemical engineering and photoemission spectroscopy. They identified all bulk branches of a higher-fold chiral fermion and revealed a multigap bulk boundary correspondence. This demonstration of multigap electronic topology will drive future research on unconventional topological responses.
PHYSICAL REVIEW LETTERS
(2023)
Article
Multidisciplinary Sciences
S. Reimers, Y. Lytvynenko, Y. R. Niu, E. Golias, B. Sarpi, L. S. I. Veiga, T. Denneulin, A. Kovacs, R. E. Dunin-Borkowski, J. Blaesser, M. Klaeui, M. Jourdan
Summary: Researchers demonstrate complete and reversible current induced switching of the Neel vector in Mn2Au, a metallic antiferromagnet, which holds promise for antiferromagnet memories. This switching is achieved with low heating and provides a long-term stable domain pattern suitable for memory applications.
NATURE COMMUNICATIONS
(2023)
Article
Multidisciplinary Sciences
Sandra Benter, Adam Jonsson, Jonas Johansson, Lin Zhu, Evangelos Golias, Lars-Erik Wernersson, Anders Mikkelsen
Summary: This study proposes the use of lithographically defined metal stacks to regulate the surface concentrations of freely diffusing synthesis elements on compound semiconductors. The geometric control of Indium droplet formation on Indium Arsenide surfaces is achieved, and the behaviours of Aluminium and Palladium as flux control agents are investigated. The study demonstrates that lithographic metal patterns can be used to control the formation of large droplets during the heating of compound semiconductors, providing a new way to steer bottom-up synthesis on-chip.
NATURE COMMUNICATIONS
(2023)
Article
Physics, Multidisciplinary
M. Krivenkov, D. Marchenko, E. Golias, M. Sajedi, A. S. Frolov, J. Sanchez-Barriga, A. Fedorov, L. V. Yashina, O. Rader, A. Varykhalov
Summary: We demonstrate that the deposition of a monolayer 2D material can significantly influence the electronic structure of the substrate. In our study, a graphene overlayer on TiC(111) changes the Fermi surface topology and modifies the electronic structure of graphene as well. The antibonding pi* band becomes occupied and observable by photoemission.
PHYSICAL REVIEW RESEARCH
(2023)
Article
Materials Science, Multidisciplinary
Alexei Nefedov, Chun Li, Kai Mueller, Anemar Bruno Kanj, Lars Heinke, Chen Luo, Kai Chen, Florin Radu, Evangelos Golias, Wolfgang Kuch, Christof Woell
Summary: Metal-organic frameworks (MOFs) are crystalline and porous, molecular solids consisting of metal nodes and organic ligands. In this study, the magnetic properties of two SURMOF-2 systems (Cu(bdc) and Cu(bpdc)) were investigated using x-ray magnetic circular dichroism. The presence of the ferromagnetic phase in these SURMOF-2 systems was confirmed. The magnetic behavior of the guest molecules differed from that of the host matrix after loading.