Denisov Artem, Bubis Anton, Piatrusha Stanislau, Titova Nadezhda, Nasibulin Albert, Becker Jonathan, Treu Julian, Ruhstorfer Daniel, Koblmüller Gregor, Tikhonov Evgeny, Khrapai Vadim
Osipyan Institute of Solid State Physics, Russian Academy of Sciences, 142432 Chernogolovka, Russia.
Department of Physics, Princeton University, Princeton, NJ 08544, USA.
Nanomaterials (Basel). 2022 Apr 25;12(9):1461. doi: 10.3390/nano12091461.
Mesoscopic superconductivity deals with various quasiparticle excitation modes, only one of them-the charge-mode-being directly accessible for conductance measurements due to the imbalance in populations of quasi-electron and quasihole excitation branches. Other modes carrying heat or even spin, valley etc. currents populate the branches equally and are charge-neutral, which makes them much harder to control. This noticeable gap in the experimental studies of mesoscopic non-equilibrium superconductivity can be filled by going beyond the conventional DC transport measurements and exploiting spontaneous current fluctuations. Here, we perform such an experiment and investigate the transport of heat in an open hybrid device based on a superconductor proximitized InAs nanowire. Using shot noise measurements, we investigate sub-gap Andreev heat guiding along the superconducting interface and fully characterize it in terms of the thermal conductance on the order of Gth∼e2/h, tunable by a back gate voltage. Understanding of the heat-mode also uncovers its implicit signatures in the non-local charge transport. Our experiments open a direct pathway to probe generic charge-neutral excitations in superconducting hybrids.
介观超导涉及各种准粒子激发模式，其中只有一种——电荷模式——由于准电子和准空穴激发分支的数量不平衡，可直接用于电导测量。其他携带热量甚至自旋、谷等电流的模式在分支中均匀分布且呈电荷中性，这使得它们更难控制。通过超越传统的直流输运测量并利用自发电流涨落，可以填补介观非平衡超导实验研究中的这一显著空白。在此，我们进行了这样一项实验，研究了基于超导体近邻化砷化铟纳米线的开放混合器件中的热输运。通过散粒噪声测量，我们研究了沿超导界面的亚能隙安德烈夫热传导，并根据约为Gth∼e2/h量级的热导率对其进行了全面表征，该热导率可通过背栅电压进行调节。对热模式的理解还揭示了其在非局部电荷输运中的隐含特征。我们的实验为探测超导混合体中的一般电荷中性激发开辟了一条直接途径。
