IN Brief:
- Low-frequency “1/f” noise remains a stubborn limiter for sensing, communications, and quantum coherence.
- UCLA researchers used correlated electron transport in charge-density-wave nanowires to suppress flicker noise below conventional limits.
- Materials that hold this behaviour at, or above, room temperature could reshape sensor front ends and on-chip interconnect strategies.
A UCLA-led team has demonstrated a route to suppressing low-frequency electronic “flicker” noise in nanowire devices, using strongly correlated electron behaviour that deviates from conventional scattering-driven transport. The result is a set of prototype devices in which measured noise falls as current increases, counter to the typical expectation that normalised low-frequency noise remains broadly constant for a given conductor geometry.
The work targets a problem that cuts across electronics and healthcare technology. Flicker noise — the 1/f component that dominates at low frequencies — sets real-world limits on phase stability in communications hardware, and it directly erodes the signal-to-noise ratio of sensors that need long integration times. In medical diagnostics, those constraints show up in biosensors and readout electronics where the signals of interest are small, slow, and easily drowned out by device-level noise.
In the study, the researchers investigated quasi-one-dimensional charge-density-wave (CDW) materials patterned into nanowire geometries. In this regime, current can be carried not only by individual electrons, but also by a collective electron–lattice condensate once an applied field exceeds a depinning threshold. The team reported ultra-low-noise behaviour in nanowires made from (TaSe₄)₂I, and similar noise suppression at room temperature in NbS₃-II, a key point for practical device design.
The mechanism hinges on correlated motion, rather than simply better materials hygiene. “Normally we think about phonons as the bad guys that are scattering electrons,” UCLA materials scientist Alexander A. Balandin said, adding that in this case “the phonons allowed electrons to jointly move along.” In other words, the interaction that usually contributes to disruption becomes part of a transport mode that reduces current fluctuations.
From a device perspective, the reported behaviour is unusual in a useful way. The researchers observed that the normalised noise spectral density decreased linearly with current in the collective transport regime, and, for (TaSe₄)₂I nanowires, did not settle into a measurable “floor” at higher bias once the sliding mode was established. For sensor electronics, that suggests a path to improved performance in operating conditions where higher current density is acceptable, or where circuit architectures can be designed to exploit the quiet regime without compromising power budgets.
The implications extend beyond medical sensing. Quantum devices and quantum-adjacent readouts are often limited by noise that couples into phase stability and coherence time, while conventional scaling trends generally make 1/f noise harder to manage as device areas shrink. CDW conductors that hold low-noise behaviour at more accessible temperatures could, in time, influence interconnect choices, low-noise amplifiers, and specialised front ends where stability is valued as highly as speed.
The team reported funding from the U.S. Office of Naval Research and the European Research Council, and it signalled further work to identify additional materials that sustain efficient CDW transport at, or above, room temperature — the threshold that separates lab curiosity from engineering option.
