ﻻ يوجد ملخص باللغة العربية
Magnetism arising from coupled spin and spatial degrees of freedom underlies the properties of a broad array of physical systems. We study here the interplay between correlations in spin and space for the quantum compass model in a finite external field, using quantum Monte Carlo methods. We find that finite temperatures cant the spin and space (bond) correlations, with increasing temperature even reorienting spin correlations between orthogonal spatial directions. We develop a coupled mean field theory to understand this effect in terms of the underlying quantum critical properties of crossed Ising chains in transverse fields and an effective field that weakens upon increasing temperature. Thermal canting offers an experimental signature of spin-bond anisotropy.
The spin-$1/2$ chain with antiferromagnetic exchange $J_1$ and $J_2 = alpha J_1$ between first and second neighbors, respectively, has both gapless and gapped ($Delta(alpha) > 0$) quantum phases at frustration $0 le alpha le 3/4$. The ground state in
Spin-reorientation phase transitions that involve the rotation of a crystal$$s magnetization have been well characterized in distorted-perovskite oxides such as the orthoferrites. In these systems spin reorientation occurs due to competing rare-earth
In cuprate superconductors, superconductivity appears below the CDW transition temperature $T_{CDW}$. However, many-body electronic states under the CDW order are still far from understood. Here, we study the development of the spin fluctuations unde
The Cu spin magnetism in La2-x-yEuySrxCuO4 (x<=0.17; y<=0.2) has been studied by means of magnetization measurements up to 14 T. Our results clearly show that in the antiferromagnetic phase Dzyaloshinsky-Moriya (DM)superexchange causes Cu spin cantin
In Mott insulators the evolution of antiferromagnetic order to superconducting or charge-density-wave-like states upon chemical doping underpins the control of quantum phases. Photo-doping can induce similar transitions on the ultrafast timescale, ho