Orbital magnetization senses topological phase transition in spin-orbit coupled α\alpha-T3T_3 system

The $\alpha$-$T_3$ system undergoes a topological phase transition(TPT) between two distinct quantum spin-Hall phases across $\alpha=0.5$ when the spin-orbit interaction of Kane-Mele type is taken into consideration. As a hallmark of such a TPT, we find that the Berry curvature and the orbital magnetic moment change their respective signs across the TPT. The trails of the TPT found in another physical observable e.g. the orbital magnetization(OM) are understood in terms of valley and spin physics. The valley-resolved OM(VROM) and the spin-resolved OM(SROM) exhibit interesting characteristics related to the valley and the spin Chern number when the chemical potential is tuned in the forbidden gap(s) of the energy spectrum. In particular, we find that the slope of the VROM vs the chemical potential in the forbidden gap changes its sign abruptly across the TPT which is also consistent with the corresponding change in the valley Chern number. Moreover, the slope of the SROM demonstrates a sudden jump by one unit of $e/h$, (where $e$ is the electronic charge and $h$ is the Planck's constant), across the TPT which is also in agreement with the corresponding change in the spin Chern number.Comment: 10 pages, 9 figure

Non-linear magnon transport in a bilayer van der Waals antiferromagnets

In this paper, we study the Berry curvature induced linear and nonlinear magnon transport in bilayer van der Waals antiferromagnets, where we deduce forms for the spin and energy currents within the semiclassical Boltzmann formalism under the relaxation time approximation. Even in the absence of the Dzyaloshinskii-Moriya interaction, if we turn on the layer-dependent electrostatic doping (ED) potential and anisotropy in the Heisenberg interactions, the linear response remains zero, whereas, we obtain a nonzero nonlinear thermal Hall response resulting from higher moments of the Berry curvature. We show that, there is a sign reversal of nonlinear thermal Hall conductivity with varying strength of ED potential, which can be potentially useful in spin-based technologies. We also comment on the momentum and temperature dependence of the relaxation time which can influence the transport properties.Comment: 16 pages. Comments welcom

RKKY coupling in Weyl semimetal thin films

We consider the effective coupling between impurity spins on surfaces of a thin-film Weyl semimetal within Ruderman-Kittel-Kasuya-Yoshida (RKKY) theory. If the spins are on the same surface, their coupling reflects the anisotropy and the spin-momentum locking of the Fermi arcs. By contrast when the spins are on opposite surfaces, their coupling is mediated by the Fermi arcs as well as by bulk states. In this case the coupling is both surprisingly strong and strongly thickness dependent, with a maximum at an optimum thickness. We demonstrate our results using analytical solutions of states in the thin-film geometry, as well using a two-surface recursive Green's function analysis of the tight-binding model.Comment: 12 pages. Comments welcom

Clinical Relevance of the Incidentaloma: A Clinician’s Viewpoint

Background: CT scanning remains one of the most routinely used diagnostic tools in a setting of InterstitialLung Disease (ILD). New and improved technologies, such as High Resolution Computer Tomography (HRCT) have revolutionized the quality of imaging, leading to a prominent increase in number of incidental findings that may or may not be of any clinical significance. The aim of this study was to evaluate the prevalence of incidental findings on thoracic CT and their clinical significance. Methods: Retrospective analysis was conducted on a cohort of 84 patients referred to our academic center as cases of ILD. Patients were referred for further evaluation between January 2000 and January 2014 and were followed over the disease course. CT scans were done annually as part of clinical management and patients were screened for any incidental findings. All incidental findings were reviewed, recorded in a clinical database and followed up on subsequent visits. Results: 25 (30%) patients were found to have incidental findings. Liver abnormalities were found in 12 (14.29 %) patients. 11(13.10 %) patients were reported to have coronary artery calcifications. 5 (5.95 %) and 3 (3.57%) patients had thyroid abnormalities and renal cysts, respectively. A malignant lesion was found in 1 patient each in liver and thyroid abnormality subgroup. Conclusion: Incidental findings are common on thoracic CT scans providing valuable and unexpected findings which warrant investigation by health care providers to exclude malignant processes