Topological Thermal Hall Conductance of Even Denominator Fractional States

by Prof. Moty Heiblum

Weizmann Institute of Science

at Physics Colloquium

Tue, 25 Jun 2024, 15:15
Ilse Katz Institute for Nanoscale Science & Technology (51), room 015

Abstract

The even denominator fractional quantum Hall (FQH) states v=5/2 and v=7/2 have been long predicted to host non-abelian quasiparticles (QPs). Their present energy-carrying neutral modes are hidden in customary conductance measurements, motivating thermal transport measurements being sensitive to all energy-carrying modes. Past ‘two-terminal’ thermal conductance measurements (K_2t*T) already proved the non-Abelian nature of the v=5/2 FQH state (supporting a single downstream Majorana edge mode); however, these measurements might be prone to lack of thermal equilibration among the counter-propagating edge modes, thus may come up with a wrong ‘topological order’ of the state. Consequently, we developed a novel thermal conductance measurement - insensitive to equilibration among counter-propagating edge modes, thus leading to the ‘topological order’ (K_xy*T) – presently, of the v=5/2 and v=7/2 states. This new method verified the non-abelian nature of the v=5/2 and v=7/2 states, both being particle-hole Pfaffian (PH-Pf) order, which supports a single upstream Majorana edge mode (in addition to the downstream charged integer and fractional modes). It is worth noting that our multiple experiments contradict the numerical calculations that predict the anti-Pf order of these states.

Banerjee et al, Nature 545, 2017; Banerjee et al, Nature 559, 2018; Dutta et al., Science 375, 2022;
Dutta et al., Science 377, 2022, Melcer et al, Nature Physics 19, 2023; Paul et al., ArXiv: 2311.15787.

Created on 08-04-2024 by Maniv, Eran (eranmaniv)
Updaded on 17-06-2024 by Maniv, Eran (eranmaniv)