Related papers: Quantum Criticality in an Organic Magnet
The competition between the tendency of magnetic moments to order at low temperatures, and the tendency of conduction electrons to shield these moments, can result in a phase transition that takes place at zero Kelvin, the quantum critical…
Using ac susceptibility, we have determined the pressure dependence of the metamagnetic critical end point temperature T* for field applied in the ab-plane in the itinerant metamagnet Sr3Ru2O7. We find that T* falls monotonically to zero as…
The S=1/2 Heisenberg model is considered on bilayer and single-layer square lattices with couplings J1, J2, and with each spin belonging to one J2-coupled dimer. A transition from a Neel to disordered ground state occurs at a critical value…
Critical thermodynamics close to a metamagnetic quantum critical endpoint (QCEP) in a metal is discussed within the framework of spin-fluctuation theory. We analyze the effective potential for the Ising order parameter that is renormalized…
Recent experiments show that double layer quantum Hall systems may have a ground state with canted antiferromagnetic order. In the experimentally accessible vicinity of a quantum critical point, the order vanishes at a temperature T_{KT} =…
Spin-orbit coupled bosons can exhibit rich equilibrium phases at low temperature and in the presence of particle-particle interactions. In the case with a 1D synthetic spin-orbit interaction, it has been observed that the ground state of a…
The ordering temperature of a quasi-one-dimensional system, consisting of weakly interacting quantum spin-1/2 chains with antiferromagnetic spin-frustrating couplings (or zig-zag ladder) is calculated. The results show that a quantum…
We present here a rare example of electronuclear quantum criticality in a metal. The compound YbCu4.6Au0.4 is located at an unconventional quantum critical point (QCP). In this material the relevant Kondo and RKKY exchange interactions are…
CePdAl with Ce $4f$ moments forming a distorted kagom\'e network is one of the scarce materials exhibiting Kondo physics and magnetic frustration simultaneously. As a result, antiferromagnetic (AF) order setting in at $T_{\mathrm{N}} =…
Several quantum critical compounds have been argued to have multiple instabilities towards orders with distinct dynamical exponents. We present an analysis of a quantum multicritical point in an itinerant magnet with competition between…
The quartic confining potential has emerged as a key ingredient to obtain fast rotating vortices in BEC as well as observation of quantum phase transitions in optical lattices. We calculate the critical temperature $T_c$ of bosons at which…
We report spontaneous appearance of antiferromagnetic order in a model gapped quantum paramagnet Ni(Cl$_{1-x}$Br$_x$)$_2$$\cdot$4SC(NH$_2$)$_2$ induced by a change in bromine concentration x. This transition is qualitatively similar to a z…
We report experimental and theoretical studies on the magnetic and thermodynamic properties of NIT-2Py, a free radical-based organic magnet. From magnetization and specific heat measurements we establish the temperature versus magnetic…
We report detailed dc and ac magnetic susceptibilities, specific heat, and thermal conductivity measurements on the frustrated magnet ZnCr$_2$Se$_4$. At low temperatures, with increasing magnetic field, this spinel material goes through a…
We present a study of the magnetic properties of Zr1-xNbxZn2, using an Arrott plot analysis of the magnetization. The Curie temperature TC is suppressed to zero temperature for Nb concentration xC=0.083+/-0.002, while the spontaneous moment…
We consider self-magnetization of charged and neutral vector bosons bearing a magnetic moment in a gas and in vacuum. For charged vector bosons (W bosons) a divergence of the magnetization in both the medium and the electroweak vacuum…
Small changes in an external parameter can often lead to dramatic qualitative changes in the lowest energy quantum mechanical ground state of a correlated electron system. In anisotropic crystals, such as the high temperature…
The theory of deconfined quantum critical points describes phase transitions at temperature T = 0 outside the standard paradigm, predicting continuous transformations between certain ordered states where conventional theory requires…
Piperazinium Hexachlorodicuprate (PHCC) is shown to be a frustrated quasi-two-dimensional quantum Heisenberg antiferromagnet with a gapped spectrum. Zero-field inelastic neutron scattering and susceptibility and specific heat measurements…
We report on results of specific heat measurements on single crystals of the frustrated quasi-2D spin-1/2 antiferromagnet Cs_2CuCl_4 (T_N=0.595 K) in external magnetic fields B<12 T and for temperatures T>30 mK. Decreasing B from high…