Prophylactic Dual Catheter Technique to Prevent Side Branch Snowplowing Complications during Angioplasty and Stenting

Objective

Angioplasty and Stenting of intracranial atherosclerotic lesions have a higher complication rate and a large proportion of this is attributable to side branch arterial occlusion from forceful displacement of the atheroma into the ostia or snowplowing effect. This can result in severe disabilities when it result in small infarcts involving eloquent areas in the posterior circulation or the motor tracts.

Materials and Methods

We present a series of 6 cases utilizing a new dual catheter technique for maintaining the patency of at-risk vessels during angioplasty and stenting. There are several methods previously described to help reduce the incidence of stroke but because they do not have a physical presence in the ostia to protect it, they are unable to guarantee the patency of the vessel.

Results

All 6 patients underwent angioplasty and stenting with the technique. The patients were assessed for complications with post-procedure magnetic resonance imaging and no complications were found.

Conclusion

In this preliminary series, the dual catheter technique appears to safe and effective in preventing occlusion of the adjacent branch arteries. This technique may facilitate the use of the Wingspan stent in the treatment of intracranial atherosclerotic stenotic segments by reducing the risk of peri-procedural stroke.

[Effect of artesunate on the transplantation tumor of parotid gland in the nude mice with adenoid cystic carcinoma drug resistance cell]

Objective:To observe the effect of Artesunate on the transplantation tumor of parotid gland in the nude mice with adenoid cystic carcinoma drug resistance cell and to explore its clinical application prospect as an anticancer drug.Method:Twenty male BALB/C mice were chose to set up parotid gland transplantation tumor model, then used the method of random Numbers table 20 nude mice were randomly divided into normal saline control group, positive control group DDP 2 mg/kg group, the ART of 200 mg/kg group, ART 100 mg/kg+DDP 1 mg/kg group, a total of 4 groups. Abdominal cavity injection was performed twice a day, and we measured weight of each nude mice and transplantation tumor major axis and minor axis. Treatments were conducted for 4 weeks, then the mice were sacrificed, and tumor weight was measured to calculate the inhibitory rates. The tumors were examined by HE staining to observe each tumor tissue pathological changes and by immunohistochemical method to detect Survivin expression in transplanted tumor tissue. Result:Four weeks after treatments, the inhibitory rate of DDP 2 mg/kg group was 59.86%, but this group of nude mice lost weight obviously； the ART 200 mg/kg group was 43.54%，this group of nude mice had a good mental state, and weight had gaining continuously；the ART 100 mg/kg+DDP 1 mg/kg group was 41.16%, this group of nude mice had reducing weight slightly.HE staining showed:The tumor nuclei were hyperchromatic and shrinkage, nuclear chromatin condensed and cracked into flake in the ART 200 mg/kg group, DDP 2 mg/kg group and the ART 100 mg/kg+DDP 1 mg/kg group. Conclusion:Artesunate can inhibit adenoid cystic carcinoma resistant cells NACC/DDP proliferation in nude mice in vivo and promote its apoptosis, and the side effects of Artesunate on nude mice were lower than Cisplatin.

[A randomized, single-blind, parallel-controlled and multicentre study: compare the efficacy and safety of domestic and imported human recombinant FSH in WHO group Ⅱ anovulatory infertility]

OBJECTIVE

To evaluate the efficacy and safety of domestic human recombinant FSH(rhFSH)in women with anovulation of WHO group Ⅱ.

METHODS

A randomized, blind, parallel-controlled, non-inferiority and multicenter study was performed. A total of 534 admitted to 13 hospitals from May 2008 to August 2009. There were 531 women with ovulatory disorder was included in the statistical analysis, were randomly divided into test group(domestic rhFSH, n=352)and control group(imported rhFSH, n=179). Percentage of cycle with mature follicle, ovulation rate, clinical pregnancy rate, multiple pregnancy rate, ovarian hyperstimulation syndrome(OHSS)and adverse events were observed.

RESULTS

No statistical significant differences(P>0.05)were observed between the two groups in terms of the efficiency on mature follicle[91.8%(323/352)versus 88.8%(159/179)], ovulation rate[91.3%(295/323)verus 90.6%(144/159)], clinical pregnancy rate[19.2%(62/323)verus 18.2%(29/159)], the number of the follicles<14 mm, the level of serum LH and progesterone, the thickness of endometrium on the day of hCG administration. The number of follicle≥18 mm and 14 mm≤follicle<18 mm and the level of serum estradiol on the day of hCG in the test group were significantly higher than those in the control group(P<0.05). The number of days of rhFSH administration in the test group was significantly less than that in the control group[(9.8±2.2)versus(11.4± 0.6)days, P<0.05], the dosage of rhFSH was significantly lower than that in the control group[(879 ± 419)versus(1 043±663)U, P<0.05]. The multiple pregnancy rate in the test group was significantly higher than that in the control group[21%(13/62)versu 10%(3/29), P<0.05]. The incidence of OHSS and adverse events were similar between the two groups(P>0.05), and no other adverse events were observed in test group during treatment.

CONCLUSION

Ovarian stimulation with domestic rhFSH is effective, safe and economical in women with anovulation of WHO group Ⅱ.

Distinct Electronic Structure for the Extreme Magnetoresistance in YSb

An extreme magnetoresistance (XMR) has recently been observed in several nonmagnetic semimetals. Increasing experimental and theoretical evidence indicates that the XMR can be driven by either topological protection or electron-hole compensation. Here, by investigating the electronic structure of a XMR material, YSb, we present spectroscopic evidence for a special case which lacks topological protection and perfect electron-hole compensation. Further investigations reveal that a cooperative action of a substantial difference between electron and hole mobility and a moderate carrier compensation might contribute to the XMR in YSb.

MRI audit of complications in intracranial stenosis treated with Wingspan device

OBJECTIVES

To evaluate the safety and efficacy of the Wingspan device for the treatment of symptomatic intracranial atherosclerotic stenosis (ICAS).

METHODS

We audited a prospective ongoing database of consecutive patients who received Wingspan stenting between January 2013 and December 2015. All patients underwent MRI to audit any complications during the early follow-up period. We focused on the clinical demographics, lesion characteristics, treatment results, and periprocedural complications. Functional outcomes were measured with the modified Rankin Scale (mRS) at discharge and after 3 months.

RESULTS

Intracranial stenting was performed in 50 patients (100%). Mean stenosis pre-stenting was 76.5±13.1% and post-stenting residual stenosis was 19.8±13.8%. The overall 30-day rate of procedure-related complications was 6.0% (3/50). Two patients (4%) developed in-stent restenosis, one of whom had a dissection at the middle cerebral artery. Interestingly, on the follow-up MRI scan there was a high incidence of asymptomatic diffusion-weighted imaging (DWI) hyperintensities, 46% (23/50) presumed to be due to microembolic causes. At the 90-day, 180-day, and 1-year follow-up, three patients had further strokes resulting in a total complication rate of 12%. 92% had excellent outcomes (mRS 0-1) and only one patient had deterioration of his mRS score.

CONCLUSIONS

ICAS treated by Wingspan stenting using pre-placement balloon angioplasty appears safe and effective with a high technical success rate and favorable outcomes. There is a high incidence of asymptomatic DWI hyperintensites post-procedure, but these do not appear to result in long-term sequelae.

Observation of unusual topological surface states in half-Heusler compounds LnPtBi (Ln=Lu, Y)

Topological quantum materials represent a new class of matter with both exotic physical phenomena and novel application potentials. Many Heusler compounds, which exhibit rich emergent properties such as unusual magnetism, superconductivity and heavy fermion behaviour, have been predicted to host non-trivial topological electronic structures. The coexistence of topological order and other unusual properties makes Heusler materials ideal platform to search for new topological quantum phases (such as quantum anomalous Hall insulator and topological superconductor). By carrying out angle-resolved photoemission spectroscopy and ab initio calculations on rare-earth half-Heusler compounds LnPtBi (Ln=Lu, Y), we directly observe the unusual topological surface states on these materials, establishing them as first members with non-trivial topological electronic structure in this class of materials. Moreover, as LnPtBi compounds are non-centrosymmetric superconductors, our discovery further highlights them as promising candidates of topological superconductors.

Heusler compounds have been predicted to host topological order with other emergent properties, which yet awaits for experimental evidence. Here, Liu et al. report a direct observation of topological surface states on half-Heusler compounds LnPtBi.

[The application of full thicknes skin graft inpartial laryngectomy for glottic carcinoma]

Objective:The aim of this study is to explore the experience and advantages of the application of full thicknes skin graft in glottic carcinoma.partial laryngectomy for glottic carcinoma.Method:One hundred and forty-three patients with glottic cancer were treated with partial laryngectomy.Among those,78 cases were repaired with full-thickness skin graft and 65 cases were repaired with sternohyoid muscular fasciae.Compared the time of extubation and the formation of granulation in laryngeal cavity after operation between the two groups.Result:In the group of full-thickness skin graft,the mean time of decannulation was 6.8 days,5 cases with growth of granulation after operation.In other group,the mean time of decannulation was 10.7 days,16 cases with growth of granulation after operation.The mean time of decannulation(t=-4.739,P<0.01) and the growth of granulation(χ²=9.379,P<0.01) are significantly different between the two groups.No laryngostenosis was found in all patients.Conclusion:The application of full-thicknes skin graft in partial laryngectomy for glottic carcinoma.can shortthe time of extubation and reduce the formation of granulation.

Comprehensive studies of interfacial strain and oxygen vacancy on metal-insulator transition of VO2 film

As a typical strong correlation material, vanadium dioxide (VO2) has attracted wide interest due to its particular metal-insulator transition (MIT) property. However, the relatively high critical temperature (T c) of ~68 °C seriously hinders its practical applications. Thus modulating the phase transition process and decreasing the T c close to room temperature have been hot topics for VO2 study. In the current work, we conducted a multi-approach strategy to control the phase transition of VO2 films, including the interfacial tensile/compressive strain and oxygen vacancies. A synchrotron radiation reciprocal space mapping technique was used to directly record the interfacial strain evolution and variations of lattice parameters. The effects of interfacial strain and oxygen vacancies in the MIT process were systematically investigated based on band structure and d-orbital electron occupation. It was suggested that the MIT behavior can be modulated through the combined effects of the interfacial strain and oxygen vacancies, achieving the distinct phase transition close to room temperature. The current findings not only provide better understanding for strain engineering and oxygen vacancies controlling phase transition behavior, but also supply a combined way to control the phase transition of VO2 film, which is essential for VO2 film based device applications in the future.

[Effects of intubating laryngeal mask airway in prevention of extubation responses in patients with hypertensive cerebral hemorrhage during general anesthesia recovery period]

OBJECTIVE

To evaluate the effects of intubating laryngeal mask airway (ILMA) in prediction of extubation responses in patients with hypertensive cerebral hemorrhage during general anesthesia recovery period.

METHODS

A total of 120 patients with hypertensive cerebral hemorrhage aged 47-71 years, with Glasgow Coma Scale (GCS)11-15 scores and American Society of Anesthesiologists (ASA) physical status Ⅰ or Ⅱ, undergoing craniotomy surgery from December 2012 to December 2014 in the Affiliated First Municipal Hospital of Fujian Medical University were randomly divided into 2 groups (n=60): tracheal intubation (Group T) and intubating laryngeal mask airway (Group I), by using a random number table. Variations of invasive arterial blood pressure and responses of endotracheal extubation were compared between two groups before and after extubation.

RESULTS

There were no significant differences in ages, sex ratio, preoperative GCS, operation time and the time from the end of operation to Train of Four stimulation (TOF) becoming to 4 between the two groups. The mean arterial pressure (MAP) at the time point of extubation (T3), 1 min (T4), 3 min (T5), 5 min (T6) after extubation were (136±20), (130±16), (128±12), (125±10) mmHg in Group T, and heart rate(HR) at these four time points were (105±11), (96±8), (92±7), (86±6) bpm, respectively. While in group I, MAP were (108±10), (106±8), (105±9), (106±7) mmHg, and HR were (75±8), (76±7), (68±5), (67±6) bpm, respectively. MAP and HR of the two groups at these four time points had significant differences (T3: t=10.91, 17.20; T4: t=13.72, 14.69; T5: t=12.54, 13.35; T6: t=13.39, 11.27; all P<0.01). During recovery, the incidences of extubation responses of group T and group I were 92% and 2%, respectively, and the difference had statistically significant (χ(2)=94.05, P<0.01). The incidences of coughing of group T and group I were 97% and 0, respectively, and the difference had statistically significant (χ(2)=148.69, P<0.01).

CONCLUSION

Compared with tracheal intubation, ILMA can decrease the incidence of extubation responses and coughing in patients with hypertensive cerebral hemorrhage during general anesthesia recovery period, and avoid cere-brovascular accidents.

[Effect of di-(2-ethylhexyl) phthalate exposure on placental development in pregnant mice]

OBJECTIVE

To investigate the effect of di-(2-ethylhexyl) phthalate (DEHP) exposure on the growth and development of placenta, uterine natural killer (uNK) cell number and angiogenesis at the maternal-fetal interface in pregnant mice.

METHODS

From day 1 of pregnancy, pregnant mice were exposed daily to DEHP by oral gavage at 125, 250, or 500 mg/kg for 13 consecutive days. The uterine and placental tissues were then harvested for HE staining and immunohistochemistry to examine the effect of DEHP exposure on the growth and development of the placenta and angiogenesis and uNK cell number at the maternal-fetal interface.

RESULTS

Compared with the control group, the mice exposed to 500 mg/kg DEHP, but not those exposed to 125 and 250 mg/kg, showed significantly reduced number of embryo implantation (P<0.05). DEHP exposure significantly increased the rate of abortion. DEHP exposure at 125, 250, and 500 mg/kg significantly and dose-dependently lowered the placental weight compared with that in the control group (0.0637±0.0133, 0.0587±0.0176, 0.0524±0.0183 g vs 0.0786±0.0143 g, respectively; P<0.01), and significantly reduced the total area of the placenta and area of spongiotrophoblasts. DEHP exposure resulted in a significant reduction in the number of fetal vascular branches, and collapse and atresia of blood vessels. The mice exposed to DEHP at 125, 250, and 500 mg/kg had significantly lowered numbers of uNK cells (83.2±10.3, 60.7±12.4, and 50.4±14.5/HP, respectively) as compared with the control group (105.1±14.2/HP) at the maternal-fetal interface (P<0.01).

CONCLUSION

DEHP exposure significantly affects the growth and development of the placenta in mice possibly by suppressing angiogenesis and reducing uNK cell number at the maternal-fetal interface during pregnancy.

Evolution of the Fermi surface of Weyl semimetals in the transition metal pnictide family

Topological Weyl semimetals (TWSs) represent a novel state of topological quantum matter which not only possesses Weyl fermions (massless chiral particles that can be viewed as magnetic monopoles in momentum space) in the bulk and unique Fermi arcs generated by topological surface states, but also exhibits appealing physical properties such as extremely large magnetoresistance and ultra-high carrier mobility. Here, by performing angle-resolved photoemission spectroscopy (ARPES) on NbP and TaP, we directly observed their band structures with characteristic Fermi arcs of TWSs. Furthermore, by systematically investigating NbP, TaP and TaAs from the same transition metal monopnictide family, we discovered their Fermiology evolution with spin-orbit coupling (SOC) strength. Our experimental findings not only reveal the mechanism to realize and fine-tune the electronic structures of TWSs, but also provide a rich material base for exploring many exotic physical phenomena (for example, chiral magnetic effects, negative magnetoresistance, and the quantum anomalous Hall effect) and novel future applications.

A Biomechanical Comparison of Expansive Pedicle Screws for Severe Osteoporosis: The Effects of Screw Design and Cement Augmentation

Expansive pedicle screws significantly improve fixation strength in osteoporotic spines. However, the previous literature does not adequately address the effects of the number of lengthwise slits and the extent of screw expansion on the strength of the bone/screw interface when expansive screws are used with or without cement augmentation. Herein, four designs for expansive pedicle screws with different numbers of lengthwise slits and different screw expansion levels were evaluated. Synthetic bones simulating severe osteoporosis were used to provide a comparative platform for each screw design. The prepared specimens were then tested for axial pullout failure. Regardless of screw design, screws with cement augmentation demonstrated significantly higher pullout strength than pedicle screws without cement augmentation (p < 0.001). For screws without cement augmentation, solid screws exhibited the lowest pullout strength compared to the four expansive groups (p < 0.01). No significant differences in pullout strength were observed between the expansive screws with different designs (p > 0.05). Taken together, our results show that pedicle screws combined with cement augmentation may greatly increase screw fixation regardless of screws with or without expansion. An increase in both the number of slits and the extent of screw expansion had little impact on the screw-anchoring strength. Cement augmentation is the most influential factor for improving screw pullout strength.

Changes in astrocyte functional markers and β-amyloid metabolism-related proteins in the early stages of hypercholesterolemia

Cholesterol is an essential substance for maintaining normal structure and function of the brain. But unfortunately, a long-term high-cholesterol diet can lead to a variety of pathological changes of the brain such as β-amyloid (Aβ) accumulation, Tau hyperphosphorylation, reactive gliosis, neuroinflammation, neuronal death and synaptic degeneration. These pathological changes have complex internal relations with one other, causing memory impairment and participating in the pathogenesis of Alzheimer's disease (AD). However, early hypercholesterolemia-induced events that lead to brain deterioration are not clear. To address this, 6-month-old female mice were fed a 3% cholesterol diet for 8weeks, followed by behavioral, biochemical and neuropathological analyses. The high-cholesterol-fed mice did not show neuronal and synaptic impairment or cognitive deficits compared with mice given a normal diet, but astrocytes were mildly activated with increased expression of functional markers including apolipoprotein E and aquaporin 4 in the hippocampus. Hippocampal interleukin-1β expression slightly increased, but interleukin-6 (IL-6) and tumor necrosis factor-α did not change significantly compared with those in the control group. Levels of Aβ, and its precursor protein, were unaffected, but levels of presenilin 1 and insulin-degrading enzyme (IDE), that initiate Aβ generation and degradation, respectively, increased in the hippocampus of the model mice. In addition, Tau phosphorylation levels were not different between the control and model groups. These results suggest that changes in astrocyte functional markers and Aβ metabolism proteins, which contribute to maintaining brain cholesterol and Aβ homeostasis, are early events in the process of hypercholesterolemia-related neuropathological changes.

Massive Dirac Fermion Observed in Lanthanide-Doped Topological Insulator Thin Films

The breaking of time reversal symmetry (TRS) in three-dimensional (3D) topological insulators (TIs), and thus the opening of a ‘Dirac-mass gap’ in the linearly dispersed Dirac surface state, is a prerequisite for unlocking exotic physical states. Introducing ferromagnetic long-range order by transition metal doping has been shown to break TRS. Here, we present the study of lanthanide (Ln) doped Bi₂Te₃, where the magnetic doping with high-moment lanthanides promises large energy gaps. Using molecular beam epitaxy, single-crystalline, rhombohedral thin films with Ln concentrations of up to ~35%, substituting on Bi sites, were achieved for Dy, Gd, and Ho doping. Angle-resolved photoemission spectroscopy shows the characteristic Dirac cone for Gd and Ho doping. In contrast, for Dy doping above a critical doping concentration, a gap opening is observed via the decreased spectral intensity at the Dirac point, indicating a topological quantum phase transition persisting up to room-temperature.

Control of the metal-insulator transition in VO₂ epitaxial film by modifying carrier density

External controlling the phase transition behavior of vanadium dioxide is important to realize its practical applications as energy-efficient electronic devices. Because of its relatively high phase transition temperature of 68 °C, the central challenge for VO2-based electronics, lies in finding an energy efficient way, to modulate the phase transition in a reversible and reproducible manner. In this work, we report an experimental realization of p-n heterojunctions by growing VO2 film on p-type GaN substrate. By adding the bias voltage on the p-n junction, the metal-insulator transition behavior of VO2 film can be changed continuously. It is demonstrated that the phase transition of VO2 film is closely associated with the carrier distribution within the space charge region, which can be directly controlled by the bias voltage. Our findings offer novel opportunities for modulating the phase transition of VO2 film in a reversible way as well as extending the concept of electric-field modulation on other phase transition materials.

Linear magnetoresistance caused by mobility fluctuations in n-doped Cd(3)As(2)

Cd(3)As(2) is a candidate three-dimensional Dirac semimetal which has exceedingly high mobility and nonsaturating linear magnetoresistance that may be relevant for future practical applications. We report magnetotransport and tunnel diode oscillation measurements on Cd(3)As(2), in magnetic fields up to 65 T and temperatures between 1.5 and 300 K. We find that the nonsaturating linear magnetoresistance persists up to 65 T and it is likely caused by disorder effects, as it scales with the high mobility rather than directly linked to Fermi surface changes even when approaching the quantum limit. From the observed quantum oscillations, we determine the bulk three-dimensional Fermi surface having signatures of Dirac behavior with a nontrivial Berry phase shift, very light effective quasiparticle masses, and clear deviations from the band-structure predictions. In very high fields we also detect signatures of large Zeeman spin splitting (g∼16).

Enhanced bioelectricity generation by improving pyocyanin production and membrane permeability through sophorolipid addition in Pseudomonas aeruginosa-inoculated microbial fuel cells

Improvement on electron shuttle-mediated extracellular electron transfer (EET) is of great potential to enhance the power output of MFCs. In this study, sophorolipid was added to enhance the performance of Pseudomonas aeruginosa-inoculated MFC by improving the electron shuttle-mediated EET. Upon sophorolipid addition, the current density and power density increased ∼ 1.7 times and ∼ 2.6 times, respectively. In accordance, significant enhancement on pyocyanin production (the electron shuttle) and membrane permeability were observed. Furthermore, the conditions for sophorolipid addition were optimized to achieve maximum pyocyanin production (14.47 ± 0.23 μg/mL), and 4 times higher power output was obtained compared to the control. The results substantiated that enhanced membrane permeability and pyocyanin production by sophorolipid, which promoted the electron shuttle-mediated EET, underlies the improvement of the energy output in the P. aeruginosa-inoculated MFC. It suggested that addition of biosurfactant could be a promising way to enhance the energy generation in MFCs.

A stable three-dimensional topological Dirac semimetal Cd3As2

Three-dimensional (3D) topological Dirac semimetals (TDSs) are a recently proposed state of quantum matter that have attracted increasing attention in physics and materials science. A 3D TDS is not only a bulk analogue of graphene; it also exhibits non-trivial topology in its electronic structure that shares similarities with topological insulators. Moreover, a TDS can potentially be driven into other exotic phases (such as Weyl semimetals, axion insulators and topological superconductors), making it a unique parent compound for the study of these states and the phase transitions between them. Here, by performing angle-resolved photoemission spectroscopy, we directly observe a pair of 3D Dirac fermions in Cd3As2, proving that it is a model 3D TDS. Compared with other 3D TDSs, for example, β-cristobalite BiO2 (ref. 3) and Na3Bi (refs 4, 5), Cd3As2 is stable and has much higher Fermi velocities. Furthermore, by in situ doping we have been able to tune its Fermi energy, making it a flexible platform for exploring exotic physical phenomena.

Discovery of a three-dimensional topological Dirac semimetal, Na3Bi

Three-dimensional (3D) topological Dirac semimetals (TDSs) represent an unusual state of quantum matter that can be viewed as "3D graphene." In contrast to 2D Dirac fermions in graphene or on the surface of 3D topological insulators, TDSs possess 3D Dirac fermions in the bulk. By investigating the electronic structure of Na3Bi with angle-resolved photoemission spectroscopy, we detected 3D Dirac fermions with linear dispersions along all momentum directions. Furthermore, we demonstrated the robustness of 3D Dirac fermions in Na3Bi against in situ surface doping. Our results establish Na3Bi as a model system for 3D TDSs, which can serve as an ideal platform for the systematic study of quantum phase transitions between rich topological quantum states.

Enhancement of bioelectricity generation by manipulation of the electron shuttles synthesis pathway in microbial fuel cells

Microbial fuel cells (MFCs) are promising for generating bioenergy and treating organic waste simultaneously. However, low extracellular electron transfer (EET) efficiency between electrogens and anodes remains one of the major bottlenecks in practical applications of MFCs. In this paper, pyocyanin (PYO) synthesis pathway was manipulated to improve the EET efficiency in Pseudomonas aeruginosa-inoculated MFCs. By overexpression of phzM (methyltransferase encoding gene), the maximum power density of P. aeruginosa-phzM-inoculated MFC was enhanced to 166.68 μW/cm(2), which was four folds of the original strain. In addition, the phzM overexpression strain exhibited an increase of 1.6 folds in PYO production and about a onefold decrease in the total internal resistance than the original strain, which should underlie the enhancement of the EET efficiency and the electricity power output (EPT). On the basis of these results, the manipulation of electron shuttles synthesis pathways could be an efficient approach to improve the EPT of MFCs.

Measurement of coherent polarons in the strongly coupled antiferromagnetically ordered iron-chalcogenide Fe1.02Te using angle-resolved photoemission spectroscopy

The nature of metallicity and the level of electronic correlations in the antiferromagnetically ordered parent compounds are two important open issues for the iron-based superconductivity. We perform a temperature-dependent angle-resolved photoemission spectroscopy study of Fe(1.02)Te, the parent compound for iron chalcogenide superconductors. Deep in the antiferromagnetic state, the spectra exhibit a "peak-dip-hump" line shape associated with two clearly separate branches of dispersion, characteristics of polarons seen in manganites and lightly doped cuprates. As temperature increases towards the Néel temperature (T(N)), we observe a decreasing renormalization of the peak dispersion and a counterintuitive sharpening of the hump linewidth, suggestive of an intimate connection between the weakening electron-phonon (e-ph) coupling and antiferromagnetism. Our finding points to the highly correlated nature of the Fe(1.02)Te ground state featured by strong interactions among the charge, spin, and lattice and a good metallicity plausibly contributed by the coherent polaron motion.