Exploration of the physical properties of the newly synthesized kagome superconductor LaIr3Ga2 using different exchange-correlation functionals.

LaIr3Ga2 is a kagome superconductor with a superconducting temperature (Tc) of 5.16 K. Here, we present the physical properties of the LaIr3Ga2 kagome superconductor computed via the DFT method wherein six different exchange-correlation functionals were used. The lattice parameters obtained using different functionals are reasonable, with a slight variation compared to experimental values. The bonding nature was explored. The elastic constants (Cij), moduli (B, G, Y), and Vickers hardness (Hv) were computed to disclose the mechanical behavior. The Hv values were estimated to be 2.56-3.16 GPa using various exchange-correlation functionals, indicating the softness of the kagome material. The Pugh ratio, Poisson's ratio, and Cauchy pressure revealed the ductile nature. In addition, mechanical stability was ensured based on the estimated elastic constants. The anisotropic mechanical behavior was confirmed via different anisotropic indices. The Debye temperature (ΘD), melting temperature (Tm), and minimum thermal conductivity (kmin) were calculated to characterize the thermal properties and predict the potential of LaIr3Ga2 as a thermal barrier coating material. The electronic density of states was investigated in detail. The McMillan equation was used to estimate Tc, and the electron-phonon coupling constant (λ) was calculated to explore the superconducting nature. The important optical constants were also calculated to explore its possible optoelectronic applications. The values of reflectivity in the IR-visible region are about 62% to 80%, indicating that the compound under study is suitable as a coating to reduce solar heating. The obtained parameters were compared with previously reported parameters, where available.

DFT insights into the electronic structure, mechanical behaviour, lattice dynamics and defect processes in the first Sc-based MAX phase Sc2SnC.

Here we employed the density functional theory calculations to investigate some physical properties of first Sc-based MAX phase Sc2SnC including defect processes to compare with those of existing M2SnC phases. The calculated structural properties are in good agreement with the experimental values. The new phase Sc2SnC is structurally, mechanically and dynamically stable. Sc2SnC is metallic with a mixture of covalent and ionic character. The covalency of Sc2SnC including M2SnC is mostly controlled by the effective valence. Sc2SnC in M2SnC family ranks second in the scale of deformability and softness. The elastic anisotropy level in Sc2SnC is moderate compared to the other M2SnC phases. The hardness and melting point of Sc2SnC, including M2SnC, follows the trend of bulk modulus. Like other members of the M2SnC family, Sc2SnC has the potential to be etched into 2D MXenes and has the potential to be a thermal barrier coating material.

Effects of Al substitution by Si in Ti3AlC2 nanolaminate.

Recently, a series of high-purity Ti3(Al1-xSix)C2 solid solutions with new compositions (x = 0.0, 0.2, 0.4, 0.6, 0.8 and 1.0) have been reported with interesting mechanical properties. Here, we have employed density functional theory for Ti3(Al1-xSix)C2 solid solutions to calculate a wider range of physical properties including structural, electronic, mechanical, thermal and optical. With the increase of x, a decrease of cell parameters is observed. All elastic constants and moduli increase with x. The Fermi level gradually increases, moving towards and past the upper bound of the pseudogap, when the value of x goes from zero to unity, indicating that the structural stability reduces gradually when the amount of Si increases within the Ti3(Al1-xSix)C2 system. In view of Cauchy pressure, Pugh's ratio and Poisson's ratio all compositions of Ti3(Al1-xSix)C2 are brittle in nature. Comparatively, low Debye temperature, lattice thermal conductivity and minimum thermal conductivity of Ti3AlC2 favor it to be a thermal barrier coating material. High melting temperatures implies that the solid solutions Ti3(Al1-xSix)C2 may have potential applications in harsh environments. In the visible region (1.8-3.1 eV), the minimum reflectivity of all compositions for both polarizations is above 45%, which makes them potential coating materials for solar heating reduction.

Chemically stable new MAX phase V2SnC: a damage and radiation tolerant TBC material.

Using density functional theory, the phase stability and physical properties, including structural, electronic, mechanical, thermal and vibrational with defect processes, of a newly synthesized 211 MAX phase V2SnC are investigated for the first time. The obtained results are compared with those found in the literature for other existing M2SnC (M = Ti, Zr, Hf, Nb, and Lu) phases. The formation of V2SnC is exothermic and this compound is intrinsically stable in agreement with the experiment. V2SnC has potential to be etched into 2D MXene. The new phase V2SnC and existing phase Nb2SnC are damage tolerant. V2SnC is elastically more anisotropic than Ti2SnC and less than the other M2SnC phases. The electronic band structure and Fermi surface of V2SnC indicate the possibility of occurrence of its superconductivity. V2SnC is expected to be a promising TBC material like Lu2SnC. The radiation tolerance in V2SnC is better than that in Lu2SnC.

Comparison between prostate volume and intravesical prostatic protrusion in detecting bladder outlet obstruction due to benign prostatic hyperplasia.

The objectives of this study were to determine and compare the correlation of intravesical prostatic protrusion (IPP) and prostate volume (PV) with bladder outlet obstruction (BOO). This study was conducted in the department of urology, Bangabandhu Sheikh Mujib Medical University (BSMMU), Dhaka, Bangladesh, between July 2009 to September 2010. Fifty benign prostatic hyperplasia (BPH) patients were included in the study. Their evaluation consisted of history along with International Prostate Symptoms Score (IPSS), digital rectal examination (DRE), transabdominal ultrasonography to measure prostate volume, intravesical prostatic protrusion & post voidal residual (PVR) urine and pressure-flow studies to detect bladder outflow obstruction (BOO). Statistical analysis included Unpaired 't' test, Chi-square test and Spearman's Rank correlation test. Receiver Operator Characteristic (ROC) curves were used to compare the correlation of PV and IPP with BOO. Mean prostate volume was significantly larger in bladder outlet obstructed patients (P<0.05). Mean IPP was significantly greater in obstructed patients (P<0.001). Area under ROC curve was 0.700 for PV and 0.821 for IPP. Prostate volume & intravesical prostatic protrusion measured through transabdominal ultrasonography are noninvasive and accessible method that significantly correlates with bladder outlet obstruction in patients with benign prostatic hyperplasia and the correlation of IPP is much more stronger than that of prostate volume.

A high pressure Ca-VI phase between 158 and 180 GPa: stability, electronic structure and superconductivity.

We have performed ab initio calculations for a new high pressure phase of Ca-VI between 158 and 180 GPa. The study includes elastic parameters of monocrystalline and polycrystalline aggregates, electronic band structure, lattice dynamics and superconductivity. The calculations show that the orthorhombic Pnma structure is mechanically and dynamically stable in the pressure range studied. The structure is superconducting over the entire pressure range and the calculated T(c) (24.7 K with µ* = 0.1) is maximum at 172 GPa, which is close to the experimentally observed value of 25 K at 161 GPa.