Radio Frequency Tunable Oscillator Device Based on SmB6 Microcrystal

TL;DR

This paper demonstrates a novel, compact, and tunable RF oscillator using a SmB6 microcrystal, leveraging its unique surface states and non-linear dynamics to generate frequencies from 20 Hz to 30 MHz, with potential for THz applications.

Contribution

It introduces a new type of current-controlled oscillator based on SmB6 microcrystals, exploiting their topological surface states and non-linear properties for tunable RF signal generation.

Findings

Operates as a current-controlled oscillator in the 30 MHz range

Produces large AC voltage outputs from 20 Hz to 30 MHz

Behavior matches a theoretical model of surface and bulk dynamics

Abstract

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 SmB6, 100 micron in size, works as a current-controlled oscillator in the 30 MHz frequency range. SmB6 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 non-linear 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.