Properties of the spin-momentum locked stateDoria, Mauro M.; Rodrigues, Edinardo I. B.
doi: 10.1088/1742-6596/2164/1/012064pmid: N/A
Spin-momentum locking is becoming a cornerstone for the understanding and applications of novel condensed matter systems. Here we assume that it holds locally in position space and from it predict the existence of a local magnetic field. Although residual, this local magnetic field is important because it brings the topological stability that transforms particles into quasi-particles. The present approach shows that the Rashba term is already contained in the Schrödinger kinetic energy and a Dirac linear spectrum can be obtained without invoking a Dirac equation for the particles.
63,65Cu, 139La-NMR study of Electron-doped High Temperature Cuprate Superconductor T’-La1.8Eu0.2CuO4–y F y Fukazawa, Hideto; Lee, Yongsun; Watai, Masaki; Tamura, Koma; Ohama, Tetsuo; Kohori, Yoh; Sunohara, Toshiki; Shiosaka, Kota; Nagaoka, Ryoji; Kawamata, Takayuki; Koike, Yoji
doi: 10.1088/1742-6596/2164/1/012003pmid: N/A
T’-La1.8Eu0.2CuO4–yFy(0 ≤ y ≥ 0.125) was measured by 63,6BCu and 139La NMR. This material is an electron-doped high-Tc cuprate superconductor which has Nd2CuO4-type structure (so-called T’-structure). The nuclear spin-lattice relaxation rate 1/T1 revealed that pseudogap behavior exists in the lightly electron-doped region of y ≤ 0.075 and electron doping suppresses the antiferromagnetic spin flutuations. These behaviors in electron-doped high-Tc cuprate superconductor are analogous with the optimum- and over-doped region in hole-doped type. 139 La NMR spectra shows almost no antiferromagnetic region in the samples of T’-La1.8Eu0.2CuO4–yFy.
Nanoprobe study of the electric field driven insulator-to-metal transition in GaMo4S8 Koussir, H.; Lefebvre, I.; Berthe, M.; Chernukha, Y.; Tranchant, J.; Corraze, B.; Janod, E.; Cario, L.; Grandidier, B.; Diener, P.
doi: 10.1088/1742-6596/2164/1/012046pmid: N/A
The resistive switching observed under electric pulses in Mott materials has a high potential for micro and nanoelectronics. Here we report on the study of the resistive switching observed at the surface of single crystals of the canonical Mott semiconductor GaMo4S8. The study is made using a multiprobe setup with 4 nanopositionable tips under the supervision of a high resolution scanning electron microscop. We find a resistivity of 38 Ω.cm by four-point probe measurements, in agreement with the literature. The volatile insulator to metal transition is studied with a two probes configuration for interelectrode distances varying between 4 and 200 microns. Finite element simulations are performed to determine the spatial distribution of the electric field prior to the transition. Our results are in agreement with i) an intrinsic voltage threshold of 60 mV independent of the interelectrode distance ii) a maximum electric field close to the electrodes and iii) a threshold electric field of 0.2 kV/cm.
Low-temperature physical properties of a new cubic compound CeMgZn2 Matsuoka, E; Yoshimoto, T; Sugawara, H; Sakurai, T; Ohta, H
doi: 10.1088/1742-6596/2164/1/012035pmid: N/A
Magnetic and transport properties of a new cubic compound CeMgZn2 have been examined by measuring the magnetic susceptibility, the magnetization, the electrical resistivity, and the specific heat. CeMgZn2 is a Kondo-lattice compound with trivalent Ce ions. The magnetic susceptibility measured at 0.1 T exhibits a shoulder and a cusp at TN1 = 5.4 K and TN2 = 3.1 K, respectively. TN1 and TN2 correspond to the antiferromagnetic-transition temperatures since these temperatures decrease with increasing magnetic field. The large value of the paramagnetic Curie temperature divided by TN1 (13.5) implies that TN1 is suppressed by geometrical frustration on a face-centered cubic Ce sublattice. The geometrical frustration may also be responsible for the appearance of many magnetic phases in magnetic fields.
Joint machine learning analysis of muon spectroscopy data from different materialsTula, T; Möller, G; Quintanilla, J; Giblin, S R; Hillier, A D; McCabe, E E; Ramos, S; Barker, D S; Gibson, S
doi: 10.1088/1742-6596/2164/1/012018pmid: N/A
Machine learning (ML) methods have proved to be a very successful tool in physical sciences, especially when applied to experimental data analysis. Artificial intelligence is particularly good at recognizing patterns in high dimensional data, where it usually outperforms humans. Here we applied a simple ML tool called principal component analysis (PCA) to study data from muon spectroscopy. The measured quantity from this experiment is an asymmetry function, which holds the information about the average intrinsic magnetic field of the sample. A change in the asymmetry function might indicate a phase transition; however, these changes can be very subtle, and existing methods of analyzing the data require knowledge about the specific physics of the material. PCA is an unsupervised ML tool, which means that no assumption about the input data is required, yet we found that it still can be successfully applied to asymmetry curves, and the indications of phase transitions can be recovered. The method was applied to a range of magnetic materials with different underlying physics. We discovered that performing PCA on all those materials simultaneously can have a positive effect on the clarity of phase transition indicators and can also improve the detection of the most important variations of asymmetry functions. For this joint PCA we introduce a simple way to track the contributions from different materials for a more meaningful analysis.
Electrical Resistivity Measurements of Antiferromagnetic Compound Ce3TiSb5 under PressureShinozaki, Masahiro; Motoyama, Gaku; Nishigori, Shijo; Yamaguchi, Akira; Yamane, Yu; Mutou, Tetsuya; Fujiwara, Kenji; Manago, Masahiro; Miyoshi, Kiyotaka; Sumiyama, Akihiko
doi: 10.1088/1742-6596/2164/1/012040pmid: N/A
We performed electrical resistivity measurements of Ce3TiSb5 under pressure. From the pressure dependences of antiferromagnetic ordering temperature TN and lower anomalous temperature T*, temperature–pressure phase diagram of Ce3TiSb5 up to 2.3 GPa has been constructed. T* rapidly decreases with increasing pressure and disappears around 1 GPa. TN increases with increasing pressure, however a hump structure of electrical resistivity below TN becomes small. Hence, some change for the magnetic ordered state is expected to occur in higher pressure region.
The 2020 Strongly Correlated Electron Systems ConferencePagliuso, Pascoal J. G.; Adriano, Cris; Miranda, Eduardo
doi: 10.1088/1742-6596/2164/1/011001pmid: N/A
The International Conference on Strongly Correlated Electrons systems (SCES) is one of the most traditional conferences in Condensed Matter Physics worldwide. SCES continues to bring together, in every edition, outstanding scientists working in the frontiers of the complex and advanced phenomena of this area. The SCES 2020 Edition was planned to be an in-person event in Guaruja, SP, Brazil in September of 2020 as a continuation of the successful series of the SCES conferences: Sendai (’92), San Diego (’93), Amsterdam (’94), Goa (’95), Zurich (’96), Paris (’98), Nagano (’99), Ann Arbor (’01), Krakow (’02), Karlsruhe (’04), Vienna (’05), Houston (’07), Buzios (’08), Santa Fe (’10), Cambridge (’11), Tokyo (’13), Grenoble (’14), Hangzhou (’16), Prague (’17) and Okayama (’19). Additionally, every three years since 1997, SCES has been joining the International Conference on Magnetism (ICM) held in: Cairns (’97), Recife (’00), Rome (’03), Kyoto (’06), Karlsruhe (’09), Busan (’12), Barcelona (’15), and San Francisco (’18).List of The international advisory committee, The prize committee, The publication Committee, The organizing committee, The local committee are available in this pdf.
Discord effects of inter-cluster interactions on a cluster-based Haldane state in a triangular spin tubeSugimoto, Takanori; Tohyama, Takami
doi: 10.1088/1742-6596/2164/1/012029pmid: N/A
We have recently proposed a new concept of cluster-based Haldane states supported by an inherent chirality in a triangular spin tube with equivalent inter-cluster interactions. In this state, there appear spin-1/2 degrees of freedom consisting of a real spin and a scalar chirality as edge states. With applying a magnetic field, we can observe approximately a half of magnetization of S = 1/2 spin, i.e., a quarter spin magnetization, due to symmetrization of the real spin and the chirality. Here, we consider effects of discord between two types of inter-cluster interactions, inducing anisotropic biquadratic interactions of effective S = 1 spins. The discord brings the edge magnetization nearer to an exact value of quarter spin magnetization, whereas localization of the edge states becomes worse. These effects are also confirmed in a corresponding spin-1 model.
Magnetic structure of an antiferromagnet NdRh2Zn20 investigated by powder neutron diffractionYamamoto, R.; Shimura, Y.; Umeo, K.; Takabatake, T.; Damay, F.; Mignot, J.-M.; Onimaru, T.
doi: 10.1088/1742-6596/2164/1/012053pmid: N/A
Powder neutron diffraction measurements were carried out to investigate the magnetic structure of the antiferromagnet NdRh2Zn20. The magnetic reflections observed for T ≤ 1.0 K are indexed by the propagation vector of k = (1/2, 1/2, 1/2). From the analysis of the intensity of magnetic reflections, a magnetic structure described by the Γ6 representation is proposed. The magnetic moments are parallel to the [112¯]or [1¯10]direction and stacked with a sequence of up-up-down-down along the [111] direction.