Huge permittivity and premature metallicity in Bi${}_2$O${}_2$Se single crystals

Abstract

Bi${}_2$O${}_2$Se is a promising material for next-generation semiconducting electronics. It exhibits premature metallicity on the introduction of a tiny amount of electrons, the physics behind which remains elusive. Here we report on transport and dielectric measurements in Bi${}_2$O${}_2$Se single crystals at various carrier densities. The temperature-dependent resistivity ($\rho$) 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 ($n_{\text{c}}\sim 10^{16}$ cm${}^{-3}$). The relative permittivity of the insulating sample is huge (${\epsilon }_{\text{r}}\approx 155(10)$) and varies slowly with temperature. Combined with the light effective mass, a long effective Bohr radius ($a_{\text{B}}^{\ast }\approx 36(2)$ $\text{nm}$) is derived, which provides a reasonable interpretation of the metallic prematurity according to Mott's criterion for MITs. The high electron mobility ($\mu$) at low temperatures may result from the screening of ionized scattering centers due to the huge ${\epsilon }_{\text{r}}$. Our findings shed light on the electron dynamics in two dimensional (2D) Bi${}_2$O${}_2$Se devices.

8 pages, 5 figures, accepted by SCIENCE CHINA: Physics, Mechanics & Astronomy

References in corpus (6)

• T-square resistivity without Umklapp scattering in dilute metallic Bi${}_2$O${}_2$Se
• Charge Transport in a Polar Metal
• Magnitude and Spatial Distribution Control of the Supercurrent in Bi2O2Se-Based Josephson Junction
• Spatially inhomogeneous electron state deep in the extreme quantum limit of strontium titanate
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Cited by in corpus (5)

• Giant modulation of the electron mobility in semiconductor Bi${}_2$O${}_2$Se via incipient ferroelectric phase transition
• Thermoelectric properties of Bi2O2Se single crystals
• Polar discontinuities and interfacial electronic properties of Bi${}_2$O${}_2$Se on SrTiO${}_3$
• Highly Polarizable Semiconductors and Universal Origin of Ferroelectricity in Materials with a Litharge-Type Structural Unit
• Phonon properties and unconventional heat transfer in quasi-2D $B{i}_2{O}_{2}Se$ crystal