相关论文: Stoner Transition at Finite Temperature in a 2D Is…

Several rare earth magnetic pyrochlore materials are well modeled by a spin-1/2 quantum Hamiltonian with anisotropic exchange parameters Js. For the Er2Ti2O7 material, the Js were recently determined from high-field inelastic neutron…

We perform a magneto-optical study of a two-dimensional electron systems (2DES) in the regime of the Stoner ferromagnetic instability for even quantum Hall filling factors on Mg$_x$Zn$_{1-x}$O/ZnO heterostructures. Under conditions of…

We show that two-dimensional fermions with dispersion $k^2$ or $k^4$ undergo a first-order Stoner transition to a fully spin-polarized state despite that the spin susceptibility diverges at the critical point. We extend our analysis to…

We report the observation of the transition from an ordered solid-like phase to a disordered liquid-like phase of a lattice of spikes on a ferrofluid surface submitted to horizontal sinusoidal vibrations. The melting transition occurs for a…

We study the Fermi surface topological transition of the pocket-opening type in a two dimensional Fermi liquid. We find that the paramagnetic fluctuations in an interacting Fermi liquid typically drive the transition first order at zero…

SrAl2Si2 crystallizes into either a semimetallic, CaAl2Si2-type, \alpha phase or a superconducting, BaZn2P2-type, \beta phase. We explore possible \alpha --Pc;Tc--> \beta transformations by employing pressure- and temperature-dependent…

Specific heat studies of the Sr$_{1-x}$Ba$_x$Mn$_{1-y}$Ti$_y$O$_3$ polycrystalline samples performed by the relaxation and DSC methods over the temperature range 2 - 450 K are reported. Anomalies accompanying the…

The structure of the ground state beyond the instability point of the quasiparticle system with Fermi-step momentum distribution is studied within the model of a Fermi liquid with a strong repulsive interaction. A ground state rearrangement…

In Uranium-based heavy fermion system, the 5f electrons display an intermediate character between partial localization and partial itinerancy, which makes the Kondo problem more complicated. Here we use scanning tunneling…

We revisit the one-dimensional ferromagnetic Ising spin-chain with a finite number of spins and periodic boundaries and derive analytically and verify numerically its various stationary and dynamical properties at different temperatures. In…

Undoped CoS$_2$ is an isotropic itinerant ferromagnet with a continuous or nearly continuous phase transition at $T_{\rm C} = 122$ K. In the doped CoS$_{1.9}$Se$_{0.1}$ system, the Curie temperature is lowered to $T_{\rm C} = 90$ K, and the…

An antiferromagnetic transition is observed in single crystal EuRh2As2 at a high temperature T_N = 47 K compared to the ferromagnetic Weiss temperature theta = 12 K. We show that this is, surprisingly, consistent with mean field theory. A…

We discuss a {\em family} of planar (two-dimensional) systems with the following phase strucure: a Fermi liquid, which goes by a second order transition (with non classical exponent even in mean-field) to an intermediate, inhomogeneous…

We have previously shown that the Stoner instability 2D has unconventional behavior: it is strongly first order but features a susceptibility which diverges at the transition point. Here, we analyze the Stoner transition for two-dimensional…

We present high-resolution measurements of the coefficient of thermal expansion $\alpha (T)=\partial \ln l(T)/\partial T$ of the quasi-twodimensional (quasi-2D) salts $\kappa$-(BEDT-TTF)$_2$X with X = Cu(NCS)$_2$, Cu[N(CN)$_2$]Br and…

We report thermal expansion and heat capacity studies on Li$_2$FeSiO$_4$ single crystals which enable us to investigate the critical behavior in the magnetically quasi-two-dimensional (2D) material. Pronounced $\lambda$-shaped anomalies at…

We review the non-zero temperature relaxational dynamics of quantum systems near a zero temperature, second-order phase transition. We begin with the quantum Ising chain, for which universal and exact results for the relaxation rates can be…

We study field-induced phase transitions in the two-dimensional dipolar Ising ferromagnet with a specific ratio between the exchange and dipolar constants, $\delta=1$, which exhibits a stripe-ordered phase with the width of one lattice unit…

For nearly a century, the Stoner model has dominated research in itinerant ferromagnetism, yet recent work on ultracold, optically trapped Fermi gases suggests that phase separation of spins occurs independent of long-range magnetic order.…

We study the two dimensional quantum Heisenberg antiferromagnet on the square lattice with easy-axis exchange anisotropy. By the semiclassical method called pure-quantum self-consistent harmonic approximation we analyse several…