Radio Frequency Tunable Oscillator Device Based on a SmB_{6} Microcrystal.
Radio Frequency Tunable Oscillator Device Based on a SmB_{6} Microcrystal.
复制标题
基于SmB_{6}微晶的射频可调谐振荡器器件。
作者：
Alex Stern;D. K. Efimkin;V. Galitski;Z. Fisk;J. Xia
射频可调谐振荡器是信号生成、表征和处理的重要电子元件。它们通常构造有谐振电路和“负”电阻器，例如古恩二极管，涉及复杂的结构和大的占地面积。本文报道了一块100 μm的SmB_{6}晶体在30 MHz频率范围内作为电流控制振荡器工作。SmB_{6}是一种强关联的近藤绝缘体，最近发现它具有一个稳定的表面态，这可能是由其电子结构的拓扑结构所保护的。我们利用其非线性动力学，并证明大交流电压输出的频率从20 Hz到30 MHz，通过调整一个小的直流偏置电流。这些振荡器的行为与描述耦合的表面和体态的热和电子动力学的理论模型一致。随着晶体尺寸的减小，我们预计该设备可以在更高的频率下工作，甚至在THz范围内。这种类型的振荡器可以在具有金属表面和半导体体的其他材料中实现。
Radio frequency tunable oscillators are vital electronic components for signal generation, characterization, and processing. They are often constructed with a resonant circuit and a "negative" resistor, such as a Gunn diode, involving complex structure and large footprints. Here we report that a piece of SmB_{6}, 100 μm in size, works as a current-controlled oscillator in the 30 MHz frequency range. SmB_{6} is a strongly correlated Kondo insulator that was recently found to have a robust surface state likely to be protected by the topology of its electronics structure. We exploit its nonlinear dynamics, and demonstrate large ac voltage outputs with frequencies from 20 Hz to 30 MHz by adjusting a small dc bias current. The behaviors of these oscillators agree well with a theoretical model describing the thermal and electronic dynamics of coupled surface and bulk states. With reduced crystal size we anticipate the device to work at higher frequencies, even in the THz regime. This type of oscillator might be realized in other materials with a metallic surface and a semiconducting bulk.