In this work we revisit itinerant ferromagnetism in 2D and 3D electron gases with arbitrary spin-orbit splitting and strong electron-electron interaction. We identify the resonant scattering processes close to the Fermi surface that are responsible for the instability of the ferromagnetic quantum critical point at low temperatures. In contrast to previous theoretical studies, we show that such processes cannot be fully suppressed even in presence of arbitrary spin-orbit splitting. A fully self-consistent non-perturbative treatment of the electron-electron interaction close to the phase transition shows that these resonant processes always destabilize the ferromagnetic quantum critical point and lead to a first-order phase transition. Characteristic signatures of these processes can be measured via the non-analytic dependence of the spin susceptibility on magnetic field both far away or close to the phase transition.
Reply to the comment on "Instability of the ferromagnetic quantum critical point and symmetry of the ferromagnetic ground state in 2D and 3D electron gases with arbitrary spin-orbit splitting''
Department of Physics, University of Basel（巴塞尔大学物理系）
Motivated by recent experimental processes, we systemically investigate strongly correlated spin-1 ultracold bosons trapped in a three-dimensional optical lattice in the presence of an external magnetic field. Based on a recently developed bosonic dynamical mean-field theory (BDMFT), we map out complete phase diagrams of the system for both antiferromagnetic and ferromagnetic interactions, where various phases are found as a result of the interplay of spin-dependent interaction and quadratic Zeeman energy. For antiferromagnetic interactions, the system demonstrates competing magnetic orders, i…
Comment on "Instability of the ferromagnetic quantum critical point and symmetry of the ferromagnetic ground state in two-dimensional and three-dimensional electron gases with arbitrary spin-orbit splitting"
University of Oregon（俄勒冈大学）；University of Maryland（马里兰大学）
Magnetic layered ternary chalcogenides hold great promise for future spin-optoelectronic devices in the two dimensional limit. Understanding how the properties of the materials are impacted by magnetic ordering and the spin-orbit interactions is critically needed information for the development of applications. Ultrafast transient reflectance (TR) and photocurrent (PC) spectroscopies are combined with ab initio density functional theory (DFT) calculations to investigate the band structure and photoresponse of a layered magnetic semiconductor CrSiTe3 (CST) nanosheet in the paramagnetic (PM, 300…
We have investigated the ferromagnetic phase transition of elemental Co by high-resolution neutron backscattering spectroscopy. We monitored the splitting of the nuclear levels by the hyperfine field at the Co nucleus. The energy of this hyperfine splitting is identified as the order parameter of the ferromagnetic phase transition. By measuring the temperature dependence of the energy we determined the critical exponent $β= 0.350 \pm 0.002$ and the ferromagnetic Curie temperature of $T_{\text{C}} = 1400$~K. The present result of the critical exponent agrees better with the predicted value (0.3…
A number of quantum Hall isospin ferromagnetic (QHIFM) states have been predicted in the relativistic zero Landau level (LL) of graphene monolayer. These states, especially the states at LL filling factor v = 0 of charge-neutral graphene, have been extensively explored in experiment. To date, identification of these high-field broken-symmetry states has mostly relied on macroscopic transport techniques. Here, we study splitting of the zero LL of graphene at partial filling and demonstrate a direct approach by imaging the QHIFM states at atomic scale with a scanning tunneling microscope. At hal…
