No abstract

Transition metal perovskite chalcogenides are a new class of versatile semiconductors with high absorption coefficient and luminescence efficiency. Polycrystalline materials synthesized by an iodine-catalyzed solid-state reaction show distinctive optical colors and tunable bandgaps across the visible range in photoluminescence, with one of the materials' external efficiency approaching the level of single-crystal InP and CdSe.

The low-field magnetic response of the non-centrosymmetric superconductor YPtBi (T c = 0.77 K) is investigated. Ac-susceptibility and dc-magnetization measurements provide solid evidence for bulk superconductivity with a volume fraction of ∼ 70 %. The lower critical field is surprisingly small: B c1 = 0.008 mT (T → 0). Muon spin rotation experiments in a transverse magnetic field of 0.01 T show a weak increase of the Gaussian damping rate σ T F below T c , which yields a London penetration depth λ = 1.6 ± 0.2 µm. The zero-field Kubo-Toyabe relaxation rate σ KT equals 0.129 ± 0.004 µs −1 and does not show a significant change below T c . This puts an upper bound of 0.04 mT on the spontaneous magnetic field associated with a possible odd-parity component in the superconducting order parameter.

Chalcogenide perovskites have emerged as a new class of electronic materials, but fundamental properties and applications of chalcogenide perovskites remain limited by the lack of high quality epitaxial thin films. We report epitaxial thin film growth of BaZrS3, a prototypical chalcogenide,

Neutron diffraction measurements were carried out on single crystals and powders of Yb 2 Pt 2 Pb, where Yb moments form two interpenetrating planar sublattices of orthogonal dimers, a geometry known as ShastrySutherland lattice, and are stacked along the c axis in a ladder geometry. Yb 2 Pt 2 Pb orders antiferromagnetically at T N = 2.07 K, and the magnetic structure determined from these measurements features the interleaving of two orthogonal sublattices into a 5 × 5 × 1 magnetic supercell that is based on stripes with moments perpendicular to the dimer bonds, which are along (110) and (−110). Magnetic fields applied along (110) or (−110) suppress the antiferromagnetic peaks from an individual sublattice, but leave the orthogonal sublattice unaffected, evidence for the Ising character of the Yb moments in Yb 2 Pt 2 Pb that is supported by point charge calculations. Specific heat, magnetic susceptibility, and electrical resistivity measurements concur with neutron elastic scattering results that the longitudinal critical fluctuations are gapped with E 0.07 meV. DOI: 10.1103/PhysRevB.93.104419 Much attention is focused on coupled spin-dimer systems, where frustrated magnetic interactions can lead to spin liquid ground states [1,2]. The Shastry-Sutherland lattice (SSL), consisting of planes of orthogonal dimers with intradimer exchange J and interdimer exchange J , is of particular interest as it has been exactly solved [3] to show that the ground state is ordered antiferromagnetically (AF) for J /J less than a critical value (J /J ) C and otherwise has a singlet ground state with gapped magnetic excitations. Insulating SrCu 2 (BO 3 ) 2 is an example of the SSL dimer liquid ground state [4][5][6]. Here, frustrated exchange interactions tend to localize singlet and triplet dimers into complex ordered superstructures at high fields [7][8][9], resulting in quantized plateaus in the magnetic field B dependence of the magnetization M(B) [10][11][12].Most SSL systems are magnetically ordered, where the closure of the singlet dimer gap yields a nonzero magnetization that makes AF order possible even for B = 0. The metallic RB 4 (R = Ho,Er,Tm,Tb) compounds order AF with period-doubling Néel ground states with Ising-like moments oriented perpendicular to the SSL planes [13][14][15][16]. In metallic The neutron diffraction measurements presented here demonstrate that the in-plane Ising-like Yb moments in Yb 2 Pt 2 Pb have a remarkably complex magnetic structure, with a commensurate superlattice of ordered stripes consisting of moment-bearing and magnetically compensated Yb pairs with moments perpendicular to the (110) and (−110) dimer bonds. The magnetic cell contains 200 Yb atoms, whose Ising character results in the formation of two independent and orthogonal sublattices that are separately polarized by magnetic fields along either (110) or (−110). The persistence of AF order in the surviving AF sublattice shows that the two orthogonal bonds of the B = 0 SSL are effectively decoupled in magnetic field, leading to a un...