Magnetic Breakdown in the electron-doped cuprate superconductor Nd2−x_{2-x}Cex_xCuO4_4: the reconstructed Fermi surface survives in the strongly overdoped regime

We report on semiclassical angle-dependent magnetoresistance oscillations (AMRO) and the Shubnikov-de Haas effect in the electron-overdoped cuprate superconductor Nd$_{2-x}$Ce$_x$CuO$_4$. Our data provide convincing evidence for magnetic breakdown in the system. This shows that a reconstructed multiply-connected Fermi surface persists, at least at strong magnetic fields, up to the highest doping level of the superconducting regime. Our results suggest an intimate relation between translational symmetry breaking and the superconducting pairing in the electron-doped cuprate superconductors.Comment: 5 pages, 4 figures, submitted to PR

Fermi-surface topology of the iron pnictide LaFe2_2P2_2

We report on a comprehensive de Haas--van Alphen (dHvA) study of the iron pnictide LaFe$_2$P$_2$. Our extensive density-functional band-structure calculations can well explain the measured angular-dependent dHvA frequencies. As salient feature, we observe only one quasi-two-dimensional Fermi-surface sheet, i.e., a hole-like Fermi-surface cylinder around $\Gamma$, essential for $s_\pm$ pairing, is missing. In spite of considerable mass enhancements due to many-body effects, LaFe$_2$P$_2$ shows no superconductivity. This is likely caused by the absence of any nesting between electron and hole bands.Comment: 5 pages, 4 figure

Magnetic structure in a U(Ru_0.92Rh_0.08)₂Si₂ single crystal studied by neutron diffraction in static magnetic fields up to 24 T

We report the high-field induced magnetic phase in single crystal of U(Ru0.92Rh0.08)2Si2. Our neutron study combined with high-field magnetization, shows that the magnetic phase above the first metamagnetic transition at Hc1 = 21.6 T has an uncompensated commensurate antiferromagnetic structure with propagation vector Q2 = ( 2/3 0 0) possessing two single-Q domains. U moments of 1.45 (9) muB directed along the c axis are arranged in an up-up-down sequence propagating along the a axis, in agreement with bulk measurements. The U magnetic form factor at high fields is consistent with both the U3+ and U4+ type. The low field short-range order that emerges from the pure URu2Si2 due to Rh-doping is initially strengthened by the field but disappears in the field-induced phase. The tetragonal symmetry is preserved across the transition but the a axis lattice parameter increases already at low fields. Our results are in agreement with itinerant electron model with 5f states forming bands pinned in the vicinity of the Fermi surface that is significantly reconstructed by the applied magnetic field.Comment: 5 pages, 4 figures, accepted as Rapid Communication, Physical Review B (2017

Upper critical field measurements up to 60 T in arsenic-deficient LaO_(0.9)F_(0.1)FeAs_(1-delta): Pauli limiting behaviour at high fields vs improved superconductivity at low fields

We report resistivity and upper critical field B_c2(T) data for As deficient LaO_(0.9)F_(0.1)FeAs_(1-delta) in a wide temperature and high field range up to 60 T. These disordered samples exhibit a slightly enhanced superconducting transition at T_c = 29 K and a significantly enlarged slope dB_(c2))/dT = -5.4 T/K near T_c which contrasts with a flattening of B_(c2)(T) starting near 23 K above 30 T. This flattening is interpreted as Pauli limiting behaviour (PLB) with B_(c2)(0) approx 63 T. We compare our results with B_(c2)(T)-data reported in the literature for clean and disordered samples. Whereas clean samples show no PLB for fields below 60 to 70 T, the hitherto unexplained flattening of B_(c2)(T) for applied fields H || ab observed for several disordered closely related systems is interpreted also as a manifestation of PLB. Consequences of our results are discussed in terms of disorder effects within the frame of conventional and unconventional superconductivity.Comment: 4 pages, 3 figures, submitted to RHMF09 (9th International Conference on the Research in High Magnetic Fields), Dresden, July 22-25, 200

Strain assessment in patients with aortic regurgitation undergoing transcatheter aortic valve implantation: case series.

BACKGROUND Limited data exist on strain changes after transcatheter aortic valve implantation (TAVI) in patients with aortic regurgitation (AR). CASE SUMMARY Three patients with AR undergoing TAVI showed an initial reduction in global longitudinal strain (GLS), followed by sustained GLS improvement within the first year. DISCUSSION Findings align with those of surgically treated patients with AR. There is a possible superiority of GLS to left ventricular end-diastolic diameter ratio in assessing patients with severe volume overload

Computed tomography anatomic predictors of outcomes in patients undergoing tricuspid transcatheter edge-to-edge repair.

AIM To identify anatomical computed tomography (CT) predictors of procedural and clinical outcomes in patients undergoing tricuspid transcatheter edge-to-edge repair (T-TEER). METHODS AND RESULTS Consecutive patients undergoing T-TEER between March 2018 to December 2022 who had cardiac CT prior to the procedure were included. CT scans were automatically analyzed using a dedicated software that employs deep learning techniques to provide precise anatomical measurements and volumetric calculations. Technical success was defined as successful placement of at least one implant in the planned anatomic location without single leaflet device attachment. Procedural success was defined as tricuspid regurgitation reduction to moderate or less. Procedural complexity was assessed by measuring the fluoroscopy time. The clinical endpoint was a composite of death, heart failure hospitalization, or tricuspid re-intervention throughout two years. A total of 33 patients (63.6% male) were included. Procedural success was achieved in 22 patients (66.7%). Shorter end-systolic (ES) height between the inferior vena cava (IVC) and tricuspid annulus (TA) (r ​= ​- 0.398, p ​= ​0.044) and longer ES RV length (r ​= ​0.551, p ​= ​0.006) correlated with higher procedural complexity. ES RV length was independently associated with lower technical(adjusted Odds ratio [OR] 0.812 [95% CI 0.665-0.991], p ​= ​0.040) and procedural success (adjusted OR 0.766, CI [0.591-0.992], p ​= ​0.043). Patients with ES right ventricular (RV) length of >77.4 ​mm had a four-fold increased risk of experiencing the composite clinical endpoint compared to patients with ES RV length ≤77.4 ​mm (HR ​= ​3.964 [95% CI, 1.018-15.434]; p ​= ​0,034]). CONCLUSION CT-derived RV length and IVC-to-TA height may be helpful to identify patients at increased risk for procedural complexity and adverse outcomes when undergoing T-TEER. CT provides valuable information for preprocedural decision-making and device selection