Magnetic impurity in a Weyl semimetal

Abstract

We utilize the variational method to study the Kondo screening of a spin-1/2 magnetic impurity in a three-dimensional (3D) Weyl semimetal with two Weyl nodes along the kz-axis. The model reduces to a 3D Dirac semimetal when the separation of the two Weyl nodes vanishes. When the chemical potential lies at the nodal point, µ = 0, the impurity spin is screened only if the coupling between the impurity and the conduction electron exceeds a critical value. For finite but small µ, the impurity spin is weakly bound due to the low density of state, which is proportional to µ 2 , contrary to that in a 2D Dirac metal such as graphene and 2D helical metal where the density of states is proportional to |µ|. The spin-spin correlation function Juv(r) between the spin v-component of the magnetic impurity at the origin and the spin u-component of a conduction electron at spatial point r, is found to be strongly anisotropic due to the spin-orbit coupling, and it decays in the power-law. The main difference of the Kondo screening in 3D Weyl semimetals and in Dirac semimetals is in the spin x-(y-) component of the correlation function in the spatial direction of the z-axis.

Single magnetic impurity in tilted Dirac surface states

“…The Kondo screening in topological semimetals using the same trial wavefunction method had been studied in Ref. 35 . In order to see the spatial changes of spin-spin correlation, we choose two sets of v i (i = x, y, t) parameters, they are: (1) v x = v y = 1.0, v t = 0.5, (2) v x = 1.0, v y = 0.8, v t = 0.5 and compare the results with the counterparts in a 2D helical metal while v x = v y = 1.0, v t = 0 31 .…”

Cr doping induced negative transverse magnetoresistance in Cd3As2 thin films

“…An external magnetic field or magnetic doping can implement the breaking of the time-reversal symmetry. A few theoretical studies have predicted a Ruderman-Kittel-Kasuya-Yosida interaction and a Kondo effect among the magnetic impurities in both Dirac and Weyl semimetals [34][35][36][37], although the experimental evidence remains lacking.…”

Влияние легирования европием на магнитные свойства 3D топологического полуметалла Cd-=SUB=-3-=/SUB=-As-=SUB=-2-=/SUB=- по данным ЭСР

“…Позд-нее были обнаружены аналогичные дальнoдействующие неосциллирующие механизмы в сверхпроводниках [6,7] на длине его когерентности (∼ 10 2 ¦ ), в сильно парамаг-нитных металлах (Pd или Ni 3 Sn) [8], в кондо-изоляторах (SmB 6 ) [9] за счет поляризации зонных электронов или остова матрицы. Теория РККИ-взаимодействия в 3D топологических DSM и WSM построена недавно в рабо-тах [10][11][12]. Ранее РККИ-взаимодействие LM в графене было теоретически рассмотрено в работе [13].…”