Track morphology in SiO quartz irradiated with swift heavy ions; Thickness and edge effects

Ishikawa, Norito; Taguchi, Tomitsugu*; Ogawa, Hiroaki; Toimil-Molares, M. E.*; Trautmann, C.*

Physical Review Materials (Internet), 10(1), p.016001_1 - 016001_7, 2026/01

https://doi.org/10.1103/gw8s-vl18

Crystalline SiO quartz samples were irradiated with 1.64 GeV and 200 MeV Au ions, and the irradiation-induced nanostructures originating from ion track formation were examined using transmission electron microscopy. The analysis revealed not only homogeneous amorphous ion tracks but also tracks with a concentric core-halo structure, characterized by a low-density core along the ion path surrounded by a damaged halo region. This type of track was found exclusively in sample regions thinner than 50 nm, suggesting that a thin sample is the prerequisite for the formation of such low-density track cores. Additionally, pitted tracks with a crater-like structure were identified at the sample edges. These findings are discussed in terms of surface phenomena, such as electronic sputtering as well as the role of sample thickness and edge effects, emphasizing the critical influence of sample geometry on the formation of these complex nanostructures.

Physical properties of intergrowth compound EuCuZnP

May, A. F.*; Tabata, Chihiro; Okamoto, Satoshi*; Ortiz, B. R.*; Christianson, A. D.*; Yan, J.*; Kaneko, Koji; McGuire, M. A.*

Physical Review Materials (Internet), 9(2), p.024406_1 - 024406_13, 2025/02

https://doi.org/10.1103/PhysRevMaterials.9.024406

Magnetic excitations in the noncentrosymmetric magnet SrMnSiO

Kawamata, Masahiro*; Pang, X.*; Murakawa, Hiroshi*; Kawamura, Seiko; Nakajima, Kenji; Masuda, Hidetoshi*; Fujita, Masaki*; Hanasaki, Noriaki*; Onose, Yoshinori*; Nambu, Yusuke*

Physical Review Materials (Internet), 9(1), p.014407_1 - 014407_6, 2025/01

https://doi.org/10.1103/PhysRevMaterials.9.014407

Dramatic elastic response at the critical end point in UTe

Valika, M.*; Haidamak, T.*; Cabala, A.*; Pospil, J.*; Bastien, G.*; Sechovsk, V.*; Prokleka, J.*; Yanagisawa, Tatsuya*; Opletal, P.; Sakai, Hironori; et al.

Physical Review Materials (Internet), 8(9), p.094415_1 - 094415_9, 2024/09

https://doi.org/10.1103/PhysRevMaterials.8.094415

Tuning of spin-orbit coupling in chiral molecule-incorporated two-dimensional organic-inorganic hybrid perovskite copper halides with ferromagnetic exchange interactions

Taniguchi, Koji*; Huang, P.-J.*; Sagayama, Hajime*; Kiyanagi, Ryoji; Oishi, Kazuki*; Kito, Shunsuke*; Nakamura, Yuiga*; Miyasaka, Hitoshi*

Physical Review Materials (Internet), 8(2), p.024409_1 - 024409_10, 2024/02

https://doi.org/10.1103/PhysRevMaterials.8.024409

Local atomic structures and lattice dynamics of inverse colossal barocaloric ammonium thiocyanate

Zhang, Z.*; Gong, W.; Kawakita, Yukinobu; 9 of others*

Physical Review Materials (Internet), 7(12), p.125402_1 - 125402_9, 2023/12

https://doi.org/10.1103/PhysRevMaterials.7.125402

Dynamic interaction between dislocations and obstacles in BCC iron based on atomic potentials derived using neural networks

Mori, Hideki*; Tsuru, Tomohito; Okumura, Masahiko; Matsunaka, Daisuke*; Shiihara, Yoshinori*; Itakura, Mitsuhiro

Physical Review Materials (Internet), 7(6), p.063605_1 - 063605_8, 2023/06

https://doi.org/10.1103/PhysRevMaterials.7.063605

The introduction of obstacles (e.g., precipitates) for controlling dislocation motion in molecular structures is a prevalent method for designing the mechanical strength of metals. Owing to the nanoscale size of the dislocation core ( 1 nm), atomic modeling is required to investigate the interactions between the dislocation and obstacles. However, conventional empirical potentials are not adequately accurate, in contrast to the calculations based on density functional theory (DFT). Therefore, the atomic-level details of the interactions between the dislocations and obstacles remain unclarified. To this end, this study applied an artificial neural network (ANN) framework to construct an atomic potential by leveraging the high accuracy of DFT. Using the constructed ANN potential, we investigated the dynamic interaction between the edge dislocation and obstacles in BCC iron. When the dislocation crossed the void, an ultrasmooth and symmetric half-loop was observed for the bowing-out dislocation. Except for the screw dislocation, the Peierls stress of all the dislocations predicted using the ANN was less than 100 MPa. More importantly, the results confirmed the formation of an Orowan loop in the interaction between a rigid sphere and dislocation. Furthermore, we discovered a phenomenon in which the Orowan loop disintegrated into two small loops during its interaction with the rigid sphere and dislocation.

Weyl-Kondo semimetal behavior in the chiral structure phase of CeRhSn

Iwasa, Kazuaki*; Suyama, Kazuya*; Kawamura, Seiko; Nakajima, Kenji; Raymond, S.*; Steffens, P.*; Yamada, Akira*; Matsuda, Tatsuma*; Aoki, Yuji*; Kawasaki, Ikuto; et al.

Physical Review Materials (Internet), 7(1), p.014201_1 - 014201_11, 2023/01

https://doi.org/10.1103/PhysRevMaterials.7.014201

Band gap opening in graphene by hybridization with Au (001) reconstructed surfaces

Terasawa, Tomoo; Matsunaga, Kazuya*; Hayashi, Naoki*; Ito, Takahiro*; Tanaka, Shinichiro*; Yasuda, Satoshi; Asaoka, Hidehito

Physical Review Materials (Internet), 7(1), p.014002_1 - 014002_10, 2023/01

https://doi.org/10.1103/PhysRevMaterials.7.014002

Au(001) surfaces exhibit a complex reconstructed structure [Hex-Au(001)] comprising a hexagonal surface and square bulk lattices, yielding a quasi-one-dimensional corrugated surface. When graphene was grown on this surface, the periodicity of the corrugated surface was predicted to change the electronic structure of graphene, forming bandgaps and new Dirac points. Furthermore, the graphene-Au interface is promising for bandgap generation and spin injection due to band hybridization. Here, we report the angle-resolved photoemission spectroscopy and density functional calculation of graphene on a Hex-Au(001) surface. The crossing point of the original and replica graphene bands showed no bandgap, suggesting that the one-dimensional potential was too small to modify the electronic structure. A bandgap of 0.2 eV was observed at the crossing point of the graphene and Au bands, indicating that the bandgap is generated using hybridization of the graphene and Au bands. We discussed the hybridization mechanism and concluded that the R30 configuration between graphene and Au and an isolated electronic structure of Au are essential for effective hybridization between graphene and Au. We anticipate that hybridization between graphene and Au would result in spin injection into graphene.

Birchite CdCu(PO)SO 5HO as a model antiferromagnetic spin-1/2 Heisenberg - chain

Fujihara, Masayoshi; Jeschke, H. O.*; Morita, Katsuhiro*; Kuwai, Tomohiko*; Koda, Akihiro*; Okabe, Hirotaka*; Matsuo, Akira*; Kindo, Koichi*; Mitsuda, Setsuo*

Physical Review Materials (Internet), 6(11), p.114408_1 - 114408_8, 2022/11

https://doi.org/10.1103/PhysRevMaterials.6.114408

= 1/2 Heisenberg - chain antiferromagnets have been investigated extensively due to their exotic magnetic states. Here, we report the magnetic behavior of birchite CdCu(PO)SO5HO and its effective spin model. Experimental studies by magnetic susceptibility, magnetization, heat capacity, and SR measurements indicate the absence of long-range order down to 0.4 K. Theoretical studies reveal that birchite is a model compound for the - antiferromagnetic chain: the intrachain interactions and are antiferromagnetic and their magnitude is about 100 times larger than the interchain interactions. The magnitude of is two to three times larger than that of , thus the spin gap is expected to be only a few percent of that of . The temperature dependence of the specific heat shows a broad peak at about 1 K ( 0.036 ), which suggests the presence of a spin gap.