Impurity-induced Ferromagnetism in Doped Triplet Excitonic Insulator

Abstract

The theory of impurities in excitonic insulator is investigated in the light of the recent experiments on hexaborides. First, we study the bound state around the impurity and find that the bound state emerges when $Re\Delta$ is positive. Second, we study the continuum state using Abrikosov-Gor'kov's approach. We find that the energy gap is reduced strongly when $Im\Delta =0$. Finally, we solve Bogoliubov-de Gennes equations for excitonic insulator numerically. We get the results consistent with the analytic ones. We also find that incomplete ferromagnetism appears in doped triplet excitonic insulator with impurity. We make a short qualitative discussion on the ferromagnetism of doped hexaborides using our result.

9 pages, 9 EPS figures, submitted to PRB

References in corpus (1)

• Ferromagnetism and superstructure in Ca_{1-x}La_xB_6

Cited by in corpus (6)

• Magnetic properties of HO2 thin films
• Theory of Ferromagnetism in Doped Excitonic Condensates
• Spontaneous gap opening and potential excitonic states in an ideal Dirac semimetal Ta${}_2$Pd${}_3$Te${}_5$
• Weak Ferromagnetism and Excitonic Condensates
• Theory of High \tc Ferromagnetism in $Sr{B}_6$ family: A case of Doped Spin-1 Mott insulator in a Valence Bond Solid Phase
• Excitonic Insulator and the Extended Falicov--Kimball Model Away from Half-Filling