【摘 要】
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Bi2O2Se is a promising material for next-generation semiconducting electronics.It exhibits premature metallicity on the intro-duction of a tiny amount of electrons,the physics behind which remains elusive.Here we report on transport and dielectric mea-sur
【机 构】
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Department of Physics,Zhejiang University,Hangzhou 310027,China;Key Laboratory for Quantum Materials
【出 处】
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中国科学:物理学 力学 天文学(英文版)
论文部分内容阅读
Bi2O2Se is a promising material for next-generation semiconducting electronics.It exhibits premature metallicity on the intro-duction of a tiny amount of electrons,the physics behind which remains elusive.Here we report on transport and dielectric mea-surements in Bi2O2Se single crystals at various carrier densities.The temperature-dependent resistivity (ρ) indicates a smooth evolution from the semiconducting to the metallic state.The critical concentration for the metal-insulator transition (MIT) to occur is extraordinarily low (nc~1016 cm-3).The relative permittivity of the insulating sample is huge (∈r ≈ 155(10)) and varies slowly with temperature.Combined with the light effective mass,a long effective Bohr radius (a*B ≈ 36(2) nm) is derived,which provides a reasonable interpretation of the metallic prematurity according to Mott\'s criterion for MITs.The high electron mobil-ity (μ) at low temperatures may result from the screening of ionized scattering centers due to the huge ∈r.Our findings shed light on the electron dynamics in two dimensional (2D) Bi2O2Se devices.
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