日本物理学会誌及びJournal of the Physical Society of Japanの月刊について

Annual review of condensed matter physics

Journal of Statistical Mechanics: theory and experiment

One-dimensional Bose-gas One-dimensional Heisenberg magnet Massive Thirring model Classical r-matrix Fundamentals of inverse scattering method Algebraic Bethe ansatz Quantum field theory integral models on a lattice Theory of scalar products Form factors Mean value of operator Q Assymptotics of correlation functions Temperature correlation functions Appendices References.

Quantum Inverse Scattering Method and Correlation Functions

Bright and electrostatically tunable electroluminescence from monolayer WSe2 p–n junctions is reported.

https://ebeam.mff.uw.edu/ebeamweb/resources/Publications/201403_ross_nnano_2014_26.pdf

Electrically tunable excitonic light-emitting diodes based on monolayer WSe2 p-n junctions.

Toward systematic understanding of diversity of electronic properties in low-dimensional molecular solids.

Multiferroics, showing simultaneous ordering of electrical and magnetic degrees of freedom, are remarkable materials as seen from both the academic and technological points of view. A prominent mechanism of multiferroicity is the spin-driven ferroelectricity, often found in frustrated antiferromagnets with helical spin order. There, as for conventional ferroelectrics, the electrical dipoles arise from an off-centre displacement of ions. However, recently a different mechanism, namely purely electronic ferroelectricity, where charge order breaks inversion symmetry, has attracted considerable interest. Here we provide evidence for ferroelectricity, accompanied by antiferromagnetic spin order, in a two-dimensional organic charge-transfer salt, thus representing a new class of multiferroics. We propose a charge-order-driven mechanism leading to electronic ferroelectricity in this material. Quite unexpectedly for electronic ferroelectrics, dipolar and spin order arise nearly simultaneously. This can be ascribed to the loss of spin frustration induced by the ferroelectric ordering. Hence, here the spin order is driven by the ferroelectricity, in marked contrast to the spin-driven ferroelectricity in helical magnets.

Multiferroicity in an organic charge-transfer salt that is suggestive of electric-dipole-driven magnetism

Multiferroics, showing simultaneous ordering of electrical and magnetic degrees of freedom, are remarkable materials as seen from both the academic and technological points of view. A prominent mechanism of multiferroicity is the spin-driven ferroelectricity, often found in frustrated antiferromagnets with helical spin order. There, similar to conventional ferroelectrics, the electrical dipoles arise from an off-centre displacement of ions. However, recently a different mechanism, namely purely electronic ferroelectricity, where charge order breaks inversion symmetry, has attracted considerable interest. Here we provide evidence for this exotic type of ferroelectricity, accompanied by antiferromagnetic spin order, in a two-dimensional organic charge-transfer salt, thus representing a new class of multiferroics. Quite unexpectedly for electronic ferroelectrics, dipolar and spin order arise nearly simultaneously. This can be ascribed to the loss of spin frustration induced by the ferroelectric ordering. Hence, here the spin order is driven by the ferroelectricity, in marked contrast to the spin-driven ferroelectricity in helical magnets.

Multiferroicity in an organic charge-transfer salt: Electric-dipole-driven magnetism

Quantum spin liquids—quantum states in which spins show no order even at very low temperatures—are possibly hosted in a kagome Heisenberg antiferromagnet. Using a powerful numerical method, the authors show that applying a magnetic field leads to various exotic plateau states, including two spin liquids.

/pdf/controlling-frustrated-liquids-and-solids-with-an-applied-w52mvwiv65.pdf

Controlling frustrated liquids and solids with an applied field in a kagome Heisenberg antiferromagnet.

We have measured and analyzed the dielectric constant of the dimer Mott insulator $\ensuremath{\kappa}\text{\ensuremath{-}}{(\text{BEDT-TTF})}_{2}{\text{Cu}}_{2}{(\text{CN})}_{3}$, which is known as a playground for a spin-liquid state. Most unexpectedly, this particular organic salt has nontrivial charge degrees of freedom, being characterized by a relaxor-like dielectric relaxation below around 60 K. This is ascribed to the charge disproportionation within the dimer due to the intersite Coulomb repulsion. A possible microscopic model is suggested and discussed.

Chisa Hotta

Papers

Toward systematic understanding of diversity of electronic properties in low-dimensional molecular solids.

Multiferroicity in an organic charge-transfer salt that is suggestive of electric-dipole-driven magnetism

Multiferroicity in an organic charge-transfer salt: Electric-dipole-driven magnetism

Controlling frustrated liquids and solids with an applied field in a kagome Heisenberg antiferromagnet.

Anomalous dielectric response in the dimer Mott insulator κ − ( BEDT-TTF ) 2 Cu 2 ( CN ) 3