We perform systematic first-principles calculations to investigate the spin-phonon coupling (SPC) of Cr2Ge2Te6 (CGT) monolayer (ML). It is found that the Eg phonon mode at 211.8 cm -1 may have a SPC as large as 3.19 cm -1 , as it directly alters the superexchange interaction along the Cr-Te-Cr pathway. Furthermore, the strength of SPC of the CGT ML can be further enhanced by an in-plane compressive strain. These results provide useful insights for the understanding of SPC in novel two-dimensional magnetic semiconductors and may guide the design of spintronic and spin Seebeck materials and devices.In Eq. (2) and (3), spin S for each Cr atom is 3/2. Our calculations show that 1 J =4.92 meV, 2 J =-0.31 meV, and 3 J =0.01 meV, which agrees well with previous studies [15,37]. The large FM 1 J results from the competition between the direct exchange between Cr-Cr sites and the superexchange mediated through the Te ions, and strongly depends on the Cr-Cr distance. It is conceivable that J1 changes when the CGT lattice is either stretched or compressed. This is confirmed in Fig. 2(a) which shows that 1 J , 2 J and 3 J increase rapidly with lattice expansion in a range from 6.69 Å to 6.97 Å. Especially, the slope of the black curve in Fig. 2(a) indicates that the coefficient of the variation of J1 with lattice expansion is as large as 21.13 meV/Å. Furthermore, it is obvious that the FM state becomes more stable when the lattice is
Articles you may be interested inCorrelation consistent basis sets for explicitly correlated wavefunctions: Pseudopotential-based basis sets for the post-d main group elements Ga-Rn Precise studies of the resonant energies of KLL dielectronic recombination ͑DR͒ processes of He-, Li-, Be-, B-, C-, N-, and O-like xenon ions were performed at the Shanghai Electron Beam Ion Trap ͓X. Zhu et al., Nucl. Instrum. Methods Phys. Res. B 235, 509 ͑2005͔͒, employing home developed high precision, high stability high voltage dividers. Influences from retardation by the capacitor of experimental setup, contact potential, space charge of the electron beam, and of ion neutralization, as well as fringing field effects were taken into account. The obtained resonant energies were, at an average uncertainty level of 0.03%, compared with calculation results by relativistic configuration interaction ͑RCI͒ theory, relativistic many-body perturbation theory ͑RMBPT͒, and by multiconfiguration Dirac-Fock ͑MCDF͒ theory. All the three predicted DR resonant energies by MCDF agree with our experiments. Among the 15 predictions by RMBPT, 13 are in good agreement with our experimental results. But only five out of 15 predictions by RCI calculation agree with our experimental results.
Young women in sub-Saharan Africa are disproportionally affected by HIV infection and unintended pregnancies. However, hormonal contraceptive (HC) use may influence HIV risk through changes in genital tract microbiota and inflammatory cytokines. To investigate this, 130 HIV negative adolescent females aged 15-19 years were enrolled into a substudy of UChoose, an open-label randomized crossover study (NCT02404038), comparing acceptability and contraceptive product preference as a proxy for HIV prevention delivery methods. Participants were randomized to injectable norethisterone enanthate (Net-En), combined oral contraceptives (COC) or etonorgesterol/ethinyl estradiol combined contraceptive vaginal ring (CCVR) for 16 weeks, then crossed over to another HC for 16 weeks. Cervicovaginal samples were collected at baseline, crossover and exit for characterization of the microbiota and measurement of cytokine levels; primary endpoints were cervical T cell activation, vaginal microbial diversity and cytokine concentrations. Adolescents randomized to COCs had lower vaginal microbial diversity and relative abundance of HIV risk-associated taxa compared to Net-En or CCVR. Cervicovaginal inflammatory cytokine concentrations were significantly higher in adolescents randomized to CCVR compared to COC and Net-En. This suggests that COC use may induce an optimal vaginal ecosystem by decreasing bacterial diversity and inflammatory taxa, while CCVR use is associated with genital inflammation.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.