Hot Electrons Regain Coherence in Semiconducting Nanowires

Abstract

The higher the energy of a particle is above equilibrium, the faster it relaxes because of the growing phase space of available electronic states it can interact with. In the relaxation process, phase coherence is lost, thus limiting high-energy quantum control and manipulation. In one-dimensional systems, high relaxation rates are expected to destabilize electronic quasiparticles. Here, we show that the decoherence induced by relaxation of hot electrons in one-dimensional semiconducting nanowires evolves nonmonotonically with energy such that above a certain threshold hot electrons regain stability with increasing energy. We directly observe this phenomenon by visualizing, for the first time, the interference patterns of the quasi-one-dimensional electrons using scanning tunneling microscopy. We visualize the phase coherence length of the one-dimensional electrons, as well as their phase coherence time, captured by crystallographic Fabry-Pèrot resonators. A remarkable agreement with a theoretical model reveals that the nonmonotonic behavior is driven by the unique manner in which one-dimensional hot electrons interact with the cold electrons occupying the Fermi sea. This newly discovered relaxation profile suggests a high-energy regime for operating quantum applications that necessitate extended coherence or long thermalization times, and may stabilize electronic quasiparticles in one dimension.

Quantum time mirrors for general two-band systems

“…Yet, we emphasize that the injection and coherent propagation (over several microns) of hot carriers in two-dimensional electron gases was recently achieved [44]. Furthermore, it has just been shown that high-energy carriers retain their coherence when excited far enough above the Fermi sea [45]. Moreover τ i is in the range of 1-100 ps in graphene [46] and bilayer graphene [47] at a temperature of around 1K, suggesting the implementation of an electronic QTM to be feasible.…”

Spectroscopic Visualization of a Robust Electronic Response of Semiconducting Nanowires to Deposition of Superconducting Islands

“…1(a), were grown in the <111> direction on an epi-ready (001) InAs substrate [17]. The nanowires have an hexagonal cross section obtained by low temperature growth procedure subsequent to the growth of the nanowires [18]. Epitaxial deposition of Al was carried out in-situ at room-temperature.…”

Quasiparticle energy relaxation in a gas of one-dimensional fermions with Coulomb interaction

“…[7], while peculiar features of the relaxation of very hot electrons were observed in Ref. [8]. These experiments have demonstrated the crucial role of the curvature of the spectrum of electrons.…”