A quieter state of charge and ultra-low-noise of the collective current in quasi-1D charge-density-wave nanowires.

Abstract

Electronic flicker noise limits phase stability in communication systems, reduces the sensitivity and selectivity of sensors, and degrades coherence in quantum devices. There is a strong need for unconventional materials and strategies for achieving ultra-low-noise performance in nanoscale and quantum electronics. Here, we demonstrate that in nanowires of the quasi-one-dimensional, fully gapped charge-density-wave material (TaSe₄)₂I, low-frequency electronic noise is suppressed below the limit of thermalized charge carriers in passive resistors. When the current is dominated by the sliding Frohlich condensate, the normalized noise spectral density, <math xmlns="http://www.w3.org/1998/Math/MathML"> <msub><mrow><mi>S</mi></mrow> <mrow><mi>I</mi></mrow> </msub> <mo>/</mo> <msup><mrow><mi>I</mi></mrow> <mrow><mn>2</mn></mrow> </msup> </math> , decreases linearly with current, <math xmlns="http://www.w3.org/1998/Math/MathML"><mi>I</mi></math> - a striking departure from the constant value of <math xmlns="http://www.w3.org/1998/Math/MathML"> <msub><mrow><mi>S</mi></mrow> <mrow><mi>I</mi></mrow> </msub> <mo>/</mo> <msup><mrow><mi>I</mi></mrow> <mrow><mn>2</mn></mrow> </msup> </math> , observed in conventional conductors. No residual minimum noise level is reached for the current of the electron-lattice condensate in (TaSe₄)₂I nanowires. Repeating the measurements for another charge-density wave conductor, NbS₃-II, we found a similar reduction below the normal electron limit at room temperature. Our findings signal intrinsically lower current fluctuations within a correlated electron transport regime.