Spin-orbital magnetic response of relativistic fermions with band hybridization

Araki, Yasufumi; Suenaga, Daiki*; Suzuki, Kei; Yasui, Shigehiro*

Physical Review Research (Internet), 3(2), p.023098_1 - 023098_17, 2021/05

https://doi.org/10.1103/PhysRevResearch.3.023098

Spins of relativistic fermions are related to their orbital degrees of freedom. In order to quantify the effect of hybridization between relativistic and nonrelativistic degrees of freedom on spin-orbit coupling, we focus on the spin-orbital (SO) crossed susceptibility arising from spin-orbit coupling. The SO crossed susceptibility is defined as the response function of their spin polarization to the "orbital" magnetic field, namely the effect of magnetic field on the orbital motion of particles as the vector potential. Once relativistic and nonrelativistic fermions are hybridized, their SO crossed susceptibility gets modified at the Fermi energy around the band hybridization point, leading to spin polarization of nonrelativistic fermions as well. These effects are enhanced under a dynamical magnetic field that violates thermal equilibrium, arising from the interband process permitted by the band hybridization. Its experimental realization is discussed for Dirac electrons in solids with slight breaking of crystalline symmetry or doping, and also for quark matter including dilute heavy quarks strongly hybridized with light quarks, arising in a relativistic heavy-ion collision process.

Effect of charge polarization on the coulomb barrier for cold-fusion reactions

Ichikawa, Takatoshi; Iwamoto, Akira

Physical Review C, 71(6), p.067601_1 - 067601_4, 2005/06

https://doi.org/10.1103/PhysRevC.71.067601

We estimate the decrease of the Coulomb-barrier height between colliding parters due to charge polarizations in the entrance channel for cold-fusion reactions. Since the Coulomb-repulsion force increases with increasing the proton numbers of the target and projectile such as cold-fusion reactions, it is expected that the charge distribution of the colliding nuclei is changed to some extent. The resulting charge distribution induced by this polarization decreases the interacting Coulomb energy between the colliding partners, whereas their own self energies increase due to the increase of the symmetry energy. We assume that the resulting charge displacements between protons and neutrons are the sum of the surface- and volume-charge components and estimate the extent of the charge polarization with the self energy on the basis of the droplet model. We show the difference between the charge polarization of light and heavy nuclei and the decrease of the Coulomb barrier height for synthesizing superheavy elements.

molecular dynamics study of polarization effects on ionic hydration in aqueous AlCl solution

Ikeda, Takashi; Hirata, Masaru; Kimura, Takaumi

Journal of Chemical Physics, 119(23), p.12386 - 12392, 2003/12

https://doi.org/10.1063/1.1627323

The solvation shell structure and dynamics of Al and Cl in an aqueous solution of 0.8 M AlCl are studied under ambient conditions by using molecular dynamics method. The solvation structures obtained from our simulations are in good agreement with the experimental ones for both Al and Cl. A detailed analysis of intramolecular geometry of hydration waters and dipole moments of the ingredients shows that the polarization has substantial effects on the structures and dynamics of both the cation and anion hydration shells. Implications to the metal hydrolysis of Al will also be given.

Corrosion behavior of stainless steels simulating radiation-induced segregation

Miwa, Yukio; Tsukada, Takashi

Proceedings of Symposium on Water Chemistry and Corrosion in Nuclear Power Plants in Asia 2003, p.301 - 306, 2003/00

Local composition change at grain boundaries due to radiation-induced segregation (RIS) followed by loss of corrosion resistance is considered to be a key mechanism on irradiation-assisted stress corrosion cracking (IASCC). However it is not clear that the local composition change induces the loss of corrosion resistance at grain boundaries, because RIS results in not only depletion of Cr but also enrichment of Ni and Si. This chemical composition change is different from that of thermally-sensitized stainless steels. In this study, experimental alloys were manufactured simulating the composition at grain boundaries of irradiated type 304 stainless steel and corrosion behavior of the experimental alloys was examined by weight loss measurement in 573 K water and anode polarization measurement in 1N sulfuric acid and 1mol/l sodium sulfate at 303 K. Following results were obtained: (1) In oxygenated water (DO=10ppm) at 573 K, weight loss increased with decreasing the concentration of Cr and did not depend on the concentration of Ni and Si. (2) Results of anode polarization measurements showed that alloys contained lower Cr and higher Ni and Si concentration exhibited lower corrosion potential in oxygenated, lower pH solution. In de-aerated solutions both sulfuric acid and sodium sulfate, however, there was a little influence of chemical composition on the corrosion potential.

Passivation condition of carbon steel in bentonite/sand mixture

Taniguchi, Naoki; Kawakami, Susumu; *

JNC TN8400 2001-025, 27 Pages, 2002/03

JNC-TN8400-2001-025.pdf:1.16MB

It is essential to understand the corrosion type of carbon steel under the repository conditions for the lifetime assessment of carbon steel overpack used for geological isolation of high-level radioactive waste. According to the previous study, carbon steel is hard to passivate in buffer material assuming a chemical condition range of groundwater in Japan. However, concrete support will be constructed around the overpack in the case of repository in the soft rock system and groundwater having a higher pH may infiltrate to buffer material. There is a possibility that the corrosion type of carbon steel will be influenced by the rise of the pH in groundwater. In this study, anodic polarization experiments were performed to understand the passivation condition of carbon steel in buffer material saturated with water contacted with concrete. An ordinary concrete and a low-alkalinity concrete were used in the experiment. The results of the experiments showed that the carbon steel can passivate under the condition that water having pH 13 infiltrate to the buffer material assuming present property of buffer material. If the low-alkalinity concrete is selected as the support material, passivation can not occur on carbon steel overpack. The effect of the factors of buffer material such as dry density and mixing ratio of sand on the passivation of carbon steel was also studied. The results of the study showed that the present property of buffer material is enough to prevent passivation of carbon steel.

Polarizability of silicon clusters

Mochizuki, Yuji; gren, H.*

Chemical Physics Letters, 336(5-6), p.451 - 456, 2001/03

https://doi.org/10.1016/S0009-2614(01)00176-2

no abstracts in English

Hydrogen absorption of titaniam for nuclear waste container in non-oxidizing condition

Tomari, Haruo*; *; Shimogori, Kazutoshi*; Wada, Ryutaro*; ; Taniguchi, Naoki

JNC TN8400 99-076, 100 Pages, 1999/10

JNC-TN8400-99-076.pdf:45.74MB

Effects of bentonite clay, applied potential, pH, of solution and cathodic polarization time on hydrogen absorption into titanium, which is one of the candidate materials of overpack for high-level radioactive waste container, have been investigated in artificial underground water. Considering the result at various test time and assuming the hydrogen absorption is ruled by the paraboric law, the amount of hydrogen after 1000 years exposure calculated to about 17ppm, which will be absorbed at the applied potential of -0.51 vs. SHE corresponds to equilibrium potential of hydrogen. It seems the assumption of the parabolic law and the test period are proper, because the linear relations were obtained between the amount of absorbed hydrogen and the logarithm of the averaged cathodic current and between the slopes of the lines and a square root of the test time. Titanium seems to have a life over 1000 years in deep underground repository according to assumption that about 500ppm absorbed hydrogen is critical for hydrogen embrittlement of titanium.

Development of a synthetic diamond radiation detector with a boron doped CVD diamond contact

Kaneko, Junichi; Katagiri, Masaki; Ikeda, Yujiro; Nishitani, Takeo

Nuclear Instruments and Methods in Physics Research A, 422, p.211 - 215, 1999/00

https://doi.org/10.1016/S0168-9002(98)01096-1

no abstracts in English

Time-resolved FT-ESR and cw-ESR studies on photo-initiated polymerization

Mizuta, Yukio*; Morishita, Norio; Kuwata, Keiji*

Magnetic Resonance and Related Phenomena, Volume 1, p.931 - 932, 1998/00

no abstracts in English

None

; ; *; ; Takeda, Seiichiro

PNC TN8410 97-425, 34 Pages, 1997/11

PNC-TN8410-97-425.pdf:0.97MB

None