2015/10/31 by Alex Stern, A. Stern, Dmitry K. Efimkin +6
Engineering · Physics and Astronomy · #Cold Atom Physics and Bose-Einstein Condensates #Computer science #Physics #Terahertz technology and applications #Topological Materials and Phenomena #cond-mat.mtrl-sci #cond-mat.str-el
paper · pdf · doi:10.1103/physrevlett.116.166603
published as Phys. Rev. Lett. 116, 166603 (2016) · v3 to appear in Physical Review Letters
arxiv created 2016/04/01 · openalex publication_date 2016/04/20 · arxiv updated 2016/04/27 · openalex created_date 2016/06/24 · openalex updated_date 2026/08/05
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 μm 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 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.