Giant impurity effect on anomalous Hall effect of Mn3Sn.

Mn3Sn is an anomalous Hall effect (AHE) antiferromagnet that exhibits the hysteretic AHE in antiferromagnetic (AFM) phase at room temperature. We report that whisker Mn3Sn crystals grown by the flux method exhibit a non-hysteretic AHE at mid-to-low temperatures when the whisker Mn3Sn is surrounded by a thin layer of ferromagnetic Mn2-xSn. These crystals exhibit a hysteretic AHE above 275 K due to the spin alignment of the inverse triangular lattice, which is similar to other crystals. However, upon cooling the crystal, it exhibits a non-hysteretic AHE with a spiral AFM spin structure at 100-200 K. We concluded that the non-hysteretic AHE is induced at the interface of Mn2-xSn/Mn3Sn. We believe that the scalar-spin chirality in the spiral AFM phase of Mn3Sn, modulated by Mn2-xSn through the magnetic proximity effect, produces the AHE. This discovery opens a new avenue for tailoring the AHE by magnetic layers.

Spin-Derived Electric Polarization and Chirality Density Inherent in Localized Electron Orbitals.

In solid state physics, any phase transition is commonly observed as a change in the microscopic distribution of charge, spin, or current. However, there is an exotic order parameter inherent in the localized electron orbitals that cannot be primarily captured by these three fundamental quantities. This order parameter is described as the electric toroidal multipoles connecting different total angular momenta under the spin-orbit coupling. The corresponding microscopic physical quantity is the spin current tensor on an atomic scale, which induces spin-derived electric polarization aligned circularly and the chirality density of the Dirac equation. Here, elucidating the nature of this exotic order parameter, we obtain the following general consequences that are not restricted to localized electron systems; chirality density is indispensable to unambiguously describe electronic states and it is a species of electric toroidal multipoles, just as the charge density is a species of electric multipoles. Furthermore, we derive the equation of continuity for chirality and discuss its relation to chiral anomaly and optical chirality. These findings link microscopic spin currents and chirality in the Dirac theory to the concept of multipoles and provide a new perspective for quantum states of matter.

Changes in olfactory identification function in total laryngectomy patients - A retrospective study focusing on nasal airflow-inducing maneuver usage, Open Essence misreactions, and odor cluster.

PURPOSE: We aimed to examine how the olfactory identification function of laryngectomy patients is altered by nasal airflow-inducing maneuver (NAIM), a method of olfactory rehabilitation, by analyzing incorrect and correct responses to olfactory identification tests to achieve odor classification. METHODS: Olfactory identification test (Open Essence [OE]) was administered to 46 patients who had undergone a total laryngectomy [Start group (NAIM was initiated from this study) = 17; (already) Using group = 19; and Nonuse group = 10]. The tests were immediately performed after the NAIM and after a mean duration of 8 months. RESULTS: In the Start group, changes in OE correct and incorrect responses showed a significant increase and decrease in the number of correct (p < 0.01) and "detectable but not recognizable" responses (p < 0.05), respectively. In the Using group, errors related to "same cluster" and "detectable but not recognizable" increased and decreased significantly (p < 0.05), respectively. The Nonuse group showed a trend of demonstrating a relatively lower number of correct responses (p < 0.1). Results of odor classification showed that only "putrefaction and sulfur" did not have any significant positive responses in the Start group. DISCUSSION: Evidently, the possibility of capturing changes in olfactory identification function by performing a false response analysis was observed, even if recovery appears to have stalled after long-term use of NAIM. Furthermore, including the "putrefaction and sulfur" cluster in the olfactory rehabilitation of laryngectomy patients and teaching them to consciously sniff "putrefaction and sulfur" in their daily lives is necessary.

A Questionnaire to Assess Phonation and Problems in Daily Living for Provox® Voice Prosthesis Users in Japan.

The aim of this study was to investigate the problems in daily life of Provox® users in Japan with the use of a questionnaire survey and to consider future guidance methods for these patients. We mailed questionnaires to 190 members of a Japanese laryngectomized patient group. We received 118 questionnaires with valid responses. The total voice handicap index (VHI) score was 44.1. Patients were allocated to two groups based on the type of surgery they underwent-laryngectomy or jejunum reconstruction. The VHI score was significantly lower in the simple laryngectomy group than that in the free jejunum reconstruction group (p < 0.01). Only 55.9% of the patients reported having received voice rehabilitation therapy. For other problems of daily life, many patients answered "bad/very bad" for the "smelling," "eating/drinking hot foodstuffs," "blowing nose," and "quantity of sputum" categories. Based on our results, there is a requirement for an effective rehabilitation therapy and appropriate guidance for patients with the Provox® voice prosthesis.

Effects of Nasal Airflow-Inducing Maneuver in Total Laryngectomy Patients Based on Changes to Olfactory Test Results: A Retrospective Study.

INTRODUCTION: This study aims to retrospectively examine temporal changes in three aspects, i.e., olfactory threshold test, olfactory identification test, and olfactory perception on daily living test, caused by the use of the nasal airflow-inducing maneuver (NAIM). METHODS: The olfactory threshold test (Sniffin' Sticks test), olfactory identification test (Open Essence [OE]), and olfactory perception on daily living test (self-administered odor question; SAOQ) were administered to 46 patients who had undergone a total laryngectomy (NAIM Start group: 17; Using group: 19; and Nonuse group: 10). The tests were immediately performed after the NAIM and again after an average of 8 months. RESULTS: In the NAIM Start group, all olfactory functions significantly improved in the second test compared with the first test (Sniffin' Sticks test and OE, p < 0.01 for both; self-administered, p < 0.05). Additionally, in terms of the intergroup changes among scores for the Sniffin' Sticks test and OE, the NAIM Start group showed a significant difference compared with all of the other groups (Start group > Using and Nonuse group, p < 0.01). The NAIM Using group did not exhibit any significant changes. In the NAIM Nonuse group, olfactory identification function was lower in the second test compared with the first test and showed a trend toward a significant difference (OE, p < 0.1). Temporal changes in SAOQ showed a significant increase in all intragroup comparisons. However, there were no significant differences observed in terms of the changes between the groups. CONCLUSION: The results demonstrated that even in those who were not using NAIM and undergoing olfactory rehabilitation after laryngectomy (NAIM Start group), the subsequent daily use of NAIM and voluntary rehabilitation aided in the recovery of olfactory function to the same level as that in the already using NAIM group. SAOQ results were considered because of the experimenter effect and they appeared to be unrelated to use NAIM. This study showed that in total laryngectomy patients who did not receive olfactory rehabilitation, olfactory identification was reduced.

Efficacy of Nasal Airflow-Inducing Maneuver in Laryngectomy Patients: A Retrospective Cohort Study.

OBJECTIVE: To evaluate the effectiveness of the nasal airflow-inducing maneuver (NAIM) using the Sniffin' Sticks (Burghart, Wedel, Germany) olfactory threshold test, Open Essence (OE, FUJIFILM Wako Pure Chemical Corporation, Osaka, Japan) olfactory identification test, and self-administered odor questionnaire (SAOQ) for olfactory perception in NAIM experienced and NAIM first-time groups. For NAIM first-time group, the relationships between time from laryngectomy to first NAIM, olfactory threshold, and identification ability were also evaluated. STUDY DESIGN: Retrospective cohort study. METHODS: Sixty-six patients who had undergone laryngectomy (NAIM experienced group: 23; NAIM first-time group: 43) underwent the threshold test, OE, and SAOQ. RESULTS: Mean results of the threshold test were 2.7 (±2.3) and 2.5 (±3.0) for the NAIM experienced and NAIM first-time groups, respectively, indicating no significant differences (P = .35). The mean number of correct responses in OE was 4.5 (±2.7) and 3.2 (±3.0) in the NAIM experienced and nonrehabilitation groups, respectively, indicating a higher number in the NAIM experienced group (P = .06). Mean result of SAOQ was 47.9% (±30.9%) and 25.5% (±27.0%) in the NAIM experienced and NAIM first-time groups, respectively, indicating a significantly higher result in the NAME experienced group (P = .003). There were no correlations of threshold test and identification test scores with time from laryngectomy to the first NAIM (threshold test: r = 0.03, P = .87; OE: r = -0.03, P = .87). CONCLUSION: NAIM enabled odor perception in patients who underwent laryngectomy, and SAOQ was an effective method for evaluating this. Further, olfactory tests in both groups showed that NAIM might restore olfaction irrespective of time elapsed since laryngectomy. LEVEL OF EVIDENCE: 4. Laryngoscope, 130: 2013-2018, 2020.

Large magneto-optical Kerr effect and imaging of magnetic octupole domains in an antiferromagnetic metal.

When a polarized light beam is incident upon the surface of a magnetic material, the reflected light undergoes a polarization rotation1. This magneto-optical Kerr effect (MOKE) has been intensively studied in a variety of ferro- and ferrimagnetic materials because it provides a powerful probe for electronic and magnetic properties2, 3 as well as for various applications including magneto-optical recording4. Recently, there has been a surge of interest in antiferromagnets (AFMs) as prospective spintronic materials for high-density and ultrafast memory devices, owing to their vanishingly small stray field and orders of magnitude faster spin dynamics compared to their ferromagnetic counterparts5-9. In fact, the MOKE has proven useful for the study and application of the antiferromagnetic (AF) state. Although limited to insulators, certain types of AFMs are known to exhibit a large MOKE, as they are weak ferromagnets due to canting of the otherwise collinear spin structure10-14. Here we report the first observation of a large MOKE signal in an AF metal at room temperature. In particular, we find that despite a vanishingly small magnetization of M ~0.002 µB/Mn, the non-collinear AF metal Mn3Sn15 exhibits a large zero-field MOKE with a polar Kerr rotation angle of 20 milli-degrees, comparable to ferromagnetic metals. Our first-principles calculations have clarified that ferroic ordering of magnetic octupoles in the non-collinear Néel state16 may cause a large MOKE even in its fully compensated AF state without spin magnetization. This large MOKE further allows imaging of the magnetic octupole domains and their reversal induced by magnetic field. The observation of a large MOKE in an AF metal should open new avenues for the study of domain dynamics as well as spintronics using AFMs.

A questionnaire to assess olfactory rehabilitation for laryngectomized patients (Provox voice prosthesis users) in Japan.

OBJECTIVE: We used a questionnaire to investigate olfactory function and the present state of olfactory rehabilitation for laryngectomized patients in Japan. METHODS: This study was conducted using a questionnaire survey. We mailed questionnaires to 190 members of a Japanese laryngectomized patient group (the nonprofit organization YOUSAY-KAI). The survey queried the following items: (1) basic information (age, sex, alaryngeal speech method, etc.); (2) questions about olfactory rehabilitation, such as the individual's experience of olfactory rehabilitation, the number of days from laryngectomy to the start of olfactory rehabilitation, and the location of rehabilitation (i.e., hospital or patient association); (3) free comments; and (4) the self-administered Odor Questionnaire (SAOQ). RESULTS: We received 121/190 questionnaires by the submission deadline. Of these, 105 questionnaires were valid. All 105 responders used the Provox voice prosthesis as the alaryngeal speech method. Only 4.7% (5/105) of the patients received olfactory rehabilitation in hospitals. Many comments in the free comment column included demands for olfactory rehabilitation such as "I want to know where we can have olfactory rehabilitation" and "I want to have rehabilitation if olfaction recovers." The SAOQ score was significantly higher in the rehabilitation group (mean, 42.5%) compared to the nonrehabilitation group (mean, 22.1%) (p<0.05). There was no correlation between the SAOQ score and the number of days from laryngectomy to the start of rehabilitation (r=0.08, p=0.76)． CONCLUSION: Patient demand for olfactory rehabilitation is strong, but this therapy is not widely offered to laryngectomized patients in Japan. Notably, the SAOQ scores showed that olfactory rehabilitation may have an effect, even if it is initiated after laryngectomy. We believe that when patients choose voice prosthesis for speech, their olfaction deteriorates unless they undergo olfactory rehabilitation separately from speech rehabilitation. It is therefore necessary to administer olfactory rehabilitation for laryngectomized patients who have never received olfactory rehabilitation, as well as for patients scheduled to undergo laryngectomy.

Pressure-induced anomalous valence crossover in cubic YbCu5-based compounds.

A pressure-induced anomalous valence crossover without structural phase transition is observed in archetypal cubic YbCu5 based heavy Fermion systems. The Yb valence is found to decrease with increasing pressure, indicating a pressure-induced crossover from a localized 4f 13 state to the valence fluctuation regime, which is not expected for Yb systems with conventional c-f hybridization. This result further highlights the remarkable singularity of the valence behavior in compressed YbCu5-based compounds. The intermetallics Yb2Pd2Sn, which shows two quantum critical points (QCP) under pressure and has been proposed as a potential candidate for a reentrant Yb2+ state at high pressure, was also studied for comparison. In this compound, the Yb valence monotonically increases with pressure, disproving a scenario of a reentrant non-magnetic Yb2+ state at the second QCP.

Spectroscopic evidence for a type II Weyl semimetallic state in MoTe2.

In a type I Dirac or Weyl semimetal, the low-energy states are squeezed to a single point in momentum space when the chemical potential µ is tuned precisely to the Dirac/Weyl point. Recently, a type II Weyl semimetal was predicted to exist, where the Weyl states connect hole and electron bands, separated by an indirect gap. This leads to unusual energy states, where hole and electron pockets touch at the Weyl point. Here we present the discovery of a type II topological Weyl semimetal state in pure MoTe2, where two sets of Weyl points (, ) exist at the touching points of electron and hole pockets and are located at different binding energies above EF. Using angle-resolved photoemission spectroscopy, modelling, density functional theory and calculations of Berry curvature, we identify the Weyl points and demonstrate that they are connected by different sets of Fermi arcs for each of the two surface terminations. We also find new surface 'track states' that form closed loops and are unique to type II Weyl semimetals. This material provides an exciting, new platform to study the properties of Weyl fermions.

Local Symmetry Effects in Actinide 4f X-ray Absorption in Oxides.

A systematic X-ray absorption study at actinide N6,7 (4f → 6d transitions) edges was performed for light-actinide oxides including data obtained for the first time for NpO2, PuO2, and UO3. The measurements were supported by ab initio calculations based on local-density-approximation with added 5f-5f Coulomb interaction (LDA+U). Improved energy resolution compared to common experiments at actinide L(2,3) (2p → 6d transitions) edges allowed us to resolve the major structures of the unoccupied 6d density of states (DOS) and estimate the crystal-field splittings in the 6d shell directly from the spectra of light-actinide dioxides. The measurements demonstrated an enhanced sensitivity of the N(6,7) spectral shape to changes in the compound crystal structure. For nonstoichiometric NpO(2-x), the filling of the entire band gap with Np 6d states was observed thus supporting a phase coexistence of Np metal and stoichiometric NpO2 which is in agreement with the tentative Np-O phase diagram.

Emergent loop-nodal s(±)-wave superconductivity in CeCu(2)Si(2): similarities to the iron-based superconductors.

Heavy-fermion superconductors are prime candidates for novel electron-pairing states due to the spin-orbital coupled degrees of freedom and electron correlations. Superconductivity in CeCu_{2}Si_{2} discovered in 1979, which is a prototype of unconventional (non-BCS) superconductors in strongly correlated electron systems, still remains unsolved. Here we provide the first report of superconductivity based on the advanced first-principles theoretical approach. We find that the promising candidate is an s_{±}-wave state with loop-shaped nodes on the Fermi surface, different from the widely expected line-nodal d-wave state. The dominant pairing glue is magnetic but high-rank octupole fluctuations. This system shares the importance of multiorbital degrees of freedom with the iron-based superconductors. Our findings reveal not only the long-standing puzzle in this material, but also urge us to reconsider the pairing states and mechanisms in all heavy-fermion superconductors.