Suppression of antiferromagnetic order and hybridization gap by electron- and hole-doping in the Kondo semiconductor CeOs${}_2$Al${}_{10}$

Abstract

The Kondo semiconductor CeOs${}_2$Al${}_{10}$ exhibits an antiferromagnetic (AFM) order at $T_{\mathrm{N}}=28.5$ K, whose temperature is unexpectedly high for the small ordered moment of $0.3$ ${\mu }_{\mathrm{B}}/$Ce. We have studied the effects of electron- and hole-doping on the hybridization gap and AFM order by measuring the magnetization $M$, magnetic susceptibility $\chi$, electrical resistivity $\rho$, and specific heat $C$ on single crystals of Ce(Os${}_{1-x}$Ir${}_x$)${}_2$Al${}_{10}$($x\le 0.15$) and Ce(Os${}_{1-y}$Re${}_y$)${}_2$Al${}_{10}$($y\le 0.1$). The results of $M(B)$ indicates that the AFM ordered moment ${\mu }_{\mathrm{AF}}$ changes the direction from the $c$-axis for $x=0$ to the $a$-axis for $x=0.03$. With increasing $x$ up to 0.15, $T_{\mathrm{N}}$ gradually decreases although the $4f$ electron state becomes localized and the magnitude of ${\mu }_{\mathrm{AF}}$ is increased to $1$ ${\mu }_{\mathrm{B}}/$Ce. With increasing $y$, the $4f$ electron state is more delocalized and the AFM order disappears at a small doping level $y=0.05$. In both electron- and hole-doped systems, the suppression of $T_{\mathrm{N}}$ is well correlated with the increase of the Sommerfeld coefficient $\gamma$ in $C(T)$. Furthermore, the simultaneous suppression of $T_{\mathrm{N}}$ and the semiconducting gap in $\rho (T)$ at $T>T_{\mathrm{N}}$ indicates that the presence of the hybridization gap is indispensable for the unusual AFM order in CeOs${}_2$Al${}_{10}$.

16 pages, 7 figures, submitted to Phys. Rev. B

References in corpus (2)

• muSR and inelastic neutron scattering investigations of the caged type Kondo semimetals: CeT2Al10 (T=Fe, Ru and Os)
• Magnetic ordering with reduced cerium moments in hole-doped CeOs2Al10

Cited by in corpus (10)

• Electronic Structures of CeM2Al10 (M = Fe, Ru, and Os) Studied by Soft X-ray Resonant and High-Resolution Photoemission Spectroscopies
• Quantitative study of valence and configuration interaction parameters of the Kondo semiconductors CeM2Al10 (M = Ru, Os and Fe) by means of bulk-sensitive hard x-ray photoelectron spectroscopy
• Contrasting electron and hole doping effects on the spin gap of the caged type Kondo semimetal CeOs${}_2$Al${}_{10}$: A muon spin relaxation and inelastic neutron scattering investigation
• Contrasting chemical pressure effect on the moment direction in the Kondo semiconductor CeT${}_2$Al${}_{10}$ (T = Ru,Os)
• Incommensurate spin-density-wave antiferromagnetism in CeRu${}_2$Al${}_2$B
• High temperature antiferromagnetism in Yb based heavy fermion systems proximate to a Kondo insulator
• Collapse of the $G{d}^{3+}$ ESR fine structure throughout the coherent temperature of the Gd-doped Kondo Semiconductor $CeF{e}_4{P}_{12}$
• Doping Effects on the Electronic Structure of an Anisotropic Kondo Semiconductor CeOs${}_2$Al${}_{10}$: An Optical Study with Re and Ir Substitution
• Tuning the hybridization and magnetic ground state of electron and hole doped CeOs${}_2$Al${}_{10}$: an x-ray spectroscopy study
• A crossover from Kondo semiconductor to metallic antiferromagnet with $5d$-electron doping in CeFe${}_2$Al${}_{10}$