Crossover in the magnetic response of single-crystalline Ba$_{1-x}$K$_x$Fe$_2$As$_2$ and Lifshitz critical point evidenced by Hall effect measurements

Yong Liu; Thomas A. Lograsso

doi:10.1103/PhysRevB.90.224508

paper

Crossover in the magnetic response of single-crystalline Ba $_{1 - x}$ K $_{x}$ Fe $_{2}$ As $_{2}$ and Lifshitz critical point evidenced by Hall effect measurements

arXiv:1411.7906 · doi:10.1103/PhysRevB.90.224508

Abstract

We report the doping evolution of magnetic susceptibility $χ (T)$ and Hall coefficient $R_{H}$ in high quality Ba $_{1 - x}$ K $_{x}$ Fe $_{2}$ As $_{2}$ ( $0.13 \leq x \leq 1$ ) single crystals. It is found that the normal-state magnetic susceptibility of Ba $_{1 - x}$ K $_{x}$ Fe $_{2}$ As $_{2}$ compounds undergoes a crossover from linear- $T$ dependence in the undoped and underdoped samples into KFe $_{2}$ As $_{2}$ -type magnetic response in the overdoped samples with increasing K content. Hall coefficient $R_{H}$ of underdoped sample $x$ =0.22 shows a rapid increase above spin-density-wave transition temperature $T_{S D W}$ . Below $T_{S D W}$ , it increases slowly. $R_{H}$ of optimally doped and slightly overdoped samples ( $0.34 \leq x \leq 0.65$ ) shows relative weak temperature dependence and saturation tendency below 150 K. However, $R_{H}$ of K heavily overdoped samples ( $0.80 \leq x \leq 1$ ) increases rapidly below 150 K. Meanwhile, Hall angle $co t θ_{H}$ displays a concave temperature dependence within the doping range $0.22 \leq x \leq 0.55$ , whereas it changes to a convex temperature dependence within the doping range $0.65 \leq x \leq 1$ . The dramatic change coincides with Lifshitz transition occurred around the critical doping $x$ =0.80, where ARPES measurements had confirmed that electron pocket disappears with excess hole doping in Ba $_{1 - x}$ K $_{x}$ Fe $_{2}$ As $_{2}$ system. It is suggested that the characteristic temperature $T$ * at around $120 \sim 150$ K observed in susceptibility and Hall coefficient, as well as previously reported resistivity data, may indicate an incoherence-coherence crossover in Ba $_{1 - x}$ K $_{x}$ Fe $_{2}$ As $_{2}$ system.

arXiv commentto be published in Phys. Rev. B

Crossover in the magnetic response of single-crystalline Ba $_{1 - x}$ K $_{x}$ Fe $_{2}$ As $_{2}$ and Lifshitz critical point evidenced by Hall effect measurements

Abstract

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Crossover in the magnetic response of single-crystalline Ba1−x​Kx​Fe2​As2​ and Lifshitz critical point evidenced by Hall effect measurements

Abstract

References in corpus (45)

Cited by in corpus (21)

Crossover in the magnetic response of single-crystalline Ba $_{1 - x}$ K $_{x}$ Fe $_{2}$ As $_{2}$ and Lifshitz critical point evidenced by Hall effect measurements