Extended staggered-flux phases in two-dimensional lattices

Based on the so called $t$-$\phi$ model in two-dimensional (2D) lattices, we investigate the stabilities of a class of extended staggered-flux (SF) phases (which are the extensions of the $\sqrt{2}\times\sqrt{2}$ SF phase to generalized spatial periods) against the Fermi-liquid phase. Surprisingly, when away from the nesting electron filling, some extended-SF phases take over the dominant SF phase (the $\sqrt{2}\times\sqrt{2}$ SF phase for the square lattice, a $1\times\sqrt{3}$ SF phase for the triangular one), compete with the Fermi-liquid phase in nontrivial patterns, and still occupy significant space in the phase diagram through the advantage in the total electronic kinetic energies. The results can be termed as the generalized Perierls orbital-antiferromagnetic instabilities of the Fermi-liquid phase in 2D lattice-electron models.Comment: 5 pages, 5 figure

Multiple Fermi pockets revealed by Shubnikov-de Haas oscillations in WTe2

We use magneto-transport measurements to investigate the electronic structure of WTe2 single crystals. A non-saturating and parabolic magnetoresistance is observed in the temperature range between 2.5 to 200 K and magnetic fields up to 8 T. Shubnikov - de Haas oscillations with beating patterns are observed. The fast Fourier transform of the SdH oscillations reveals three oscillation frequencies, corresponding to three pairs of Fermi pockets with comparable effective masses , m* ~ 0.31 me. By fitting the Hall resistivity, we infer the presence of one pair of electron pockets and two pairs of hole pockets, together with nearly perfect compensation of the electron-hole carrier concentration. These magnetotransport measurements reveal the complex electronic structure in WTe2, explaining the nonsaturating magnetoresistance.Comment: Submitted to journal on 1 April, 2015, 4 Figure

2-Methyl-2,4-di-4-pyridyl-2,3-dihydro-1H-1,5-benzodiazepine acetic acid solvate

In the title compound, C20H18N4·CH3COOH, the benzene ring forms dihedral angles of 81.34 (11) and 54.32 (11)° with the two pyridine rings. In the crystal, inter­molecular O—H⋯N hydrogen bonding links one 1,5-benzodiazepine mol­ecule and one acetic acid solvent mol­ecule into a dimer. These dimers, related by translation along the b axis, are further linked into chains via weak inter­molecular N—H⋯N hydrogen bonds

2,2,2-Trifluoro­ethyl 4-methyl­benzene­sulfonate

In the crystal structure of the title compound, C9H9F3O3S, inter­molecular C—H⋯O hydrogen bonds link the mol­ecules along the c-axis direction. Also present are slipped π–π stacking inter­actions between phenyl­ene rings, with perpendicular inter­planar distances of 3.55 (2) Å and centroid–centroid distances of 3.851 (2) Å