Electrical Engineering Department, ‡Materials Science and Engineering Department, and §Center for 2-Dimensional and Layered Materials, The Pennsylvania State University , University Park, Pennsylvania 16802, United States.
Nano Lett. 2015 Mar 11;15(3):1861-6. doi: 10.1021/nl504662b. Epub 2015 Feb 4.
In this work, we demonstrate abrupt, reversible switching of resistance in 1T-TaS2 using dc and pulsed sources, corresponding to an insulator-metal transition between the insulating Mott and equilibrium metallic states. This transition occurs at a constant critical resistivity of 7 mohm-cm regardless of temperature or bias conditions and the transition time is significantly smaller than abrupt transitions by avalanche breakdown in other small gap Mott insulating materials. Furthermore, this critical resistivity corresponds to a carrier density of 4.5 × 10(19) cm(-3), which compares well with the critical carrier density for the commensurate to nearly commensurate charge density wave transition. These results suggest that the transition is facilitated by a carrier driven collapse of the Mott gap in 1T-TaS2, which results in fast (3 ns) switching.
在这项工作中，我们使用直流和脉冲源演示了 1T-TaS2 中电阻的突然、可逆切换，对应于绝缘莫特态和平衡金属态之间的绝缘-金属转变。这种转变发生在一个恒定的临界电阻率为 7 兆欧-厘米，与温度或偏置条件无关，并且转变时间明显小于其他小带隙莫特绝缘材料中雪崩击穿的突然转变。此外，这个临界电阻率对应于载流子密度为 4.5×10(19)cm(-3)，与准同相与近同相电荷密度波转变的临界载流子密度相当。这些结果表明，这种转变是由 1T-TaS2 中载流子驱动的莫特能隙崩塌所促进的，从而导致快速（3ns）切换。
