Band Structure of Topological Insulator BiSbTe1.25Se1.75.

We present our angle resolved photoelectron spectroscopy (ARPES) and density functional theory results on quaternary topological insulator (TI) BiSbTe1.25Se1.75 (BSTS) confirming the non-trivial topology of the surface state bands (SSBs) in this compound. We find that the SSBs, which are are sensitive to the atomic composition of the terminating surface have a partial 3D character. Our detailed study of the band bending (BB) effects shows that in BSTS the Dirac point (DP) shifts by more than two times compared to that in Bi2Se3 to reach the saturation. The stronger BB in BSTS could be due to the difference in screening of the surface charges. From momentum density curves (MDCs) of the ARPES data we obtained an energy dispersion relation showing the warping strength of the Fermi surface in BSTS to be intermediate between those found in Bi2Se3 and Bi2Te3 and also to be tunable by controlling the ratio of chalcogen/pnictogen atoms. Our experiments also reveal that the nature of the BB effects are highly sensitive to the exposure of the fresh surface to various gas species. These findings have important implications in the tuning of DP in TIs for technological applications.

Effect of time of harvesting on yield and quality of melissa officinalis L. In doon valley, India.

A field experiment on the effect of time of harvesting on yield and quality of Melissa officinalis L. was conducted under the agroclimatic conditions of Doon valley, Uttarakhand in order to assess the performance of four harvesting times (H1-120 days, H2-140 days, H3-160 days and H4-180 days after planting). The fresh and dry herbage and oil yield of the aerial parts showed greater response in H3 i.e. harvesting at 160 days after planting, followed by H2 harvesting time. The quality of essential oil was evaluated using GC and GC-MS analysis. Geranial (24.53 %) and neral (18.80 %) were the major constituents found in the essential oil followed by trans-caryophyllene (7.70 %).

Photoemission studies of the near EF spectral weight shifts in FeSe1-xTex superconductor.

Our valence band photoelectron spectroscopic studies show a temperature dependent spectral weight transfer near the Fermi level in the Fe-based superconductor FeSe1-xTex. Using theoretical band structure calculations we have shown that the weight transfer is due to the temperature induced changes in the Fe(Se,Te)4 tetrahedra. These structural changes lead to shifts in the electron occupancy from the xz/yz and x2-y2 orbitals to the 3z2-r2 orbitals indicating a temperature induced crossover from a metallic state to an Orbital Selective Mott (OSM) Phase. Our study presents an observation of a temperature induced crossover to a low temperature OSM phase in the family of Fe chalcogenides.

Influence of Phenological Stages on Yield and Quality of Oregano (Origanum vulgare L.) Under the Agroclimatic Condition of Doon Valley (Uttarakhand).

A field experiment was conducted under the agroclimatic conditions of Doon valley, in order to determine the effects of phenological stages on herbage yield and quality of oil in oregano (Origanum vulgare L.). Plants were harvested in five phenological stages, i.e. early vegetative, late vegetative, flower initiation, full bloom, and fruit set stages. Results showed the significant effects of phenological stages on herbage, yield, and quality of oregano. Harvesting at full bloom stage showed better results in terms of herbage and oil yield. The quality of essential oil was evaluated using GC and GC/MS. Thymol content was rich in all the stages (46.90-62.26%) followed by γ-terpinene (1.11-11.75%) and p-cymene (3.11-5.32%).