Gate-Tuned Spontaneous Exciton Insulator in Double-Quantum Wells

Abstract

It was proposed that a dilute semimetal is unstable against the formation of an exciton insulator, however experimental confirmations have remained elusive. We investigate the origin of bulk energy gap in inverted InAs/GaSb quantum wells (QWs) which naturally host spatially-separated electrons and holes, using charge-neutral point density (no~po) in gated-device as a tuning parameter. We find two distinct regimes of gap formation, that for I), no >> 5x1010/cm2, a soft gap opens predominately by electron-hole hybridization; and for II), approaching the dilute limit no~ 5x1010/cm2, a hard gap opens leading to a true bulk insulator with quantized edge states. Moreover, the gap is dramatically reduced as the QWs are tuned to less dilute. We further examine the response of gaps to in-plane magnetic fields, and find that for I) the gap closes at B// > ~ 10T, consistent with hybridization while for II) the gap opens continuously for B// as high as 35T. Our analyses show that the hard gap in II) cannot be explained by single-particle hybridization. The data are remarkably consistent with the formation of a nontrivial exciton insulator in very dilute InAs/GaSb QWs.

References in corpus (6)

• Nonlocal edge state transport in the quantum spin Hall state
• Quantum Spin Hall Effect in Inverted Type II Semiconductors
• Exciton condensation and charge fractionalization in a topological insulator film
• Collective, Coherent, and Ultrastrong Coupling of 2D Electrons with Terahertz Cavity Photons
• Effective g-factors of carriers in inverted InAs/GaSb bilayers
• Stability of High-Density Two-Dimensional Excitons against a Mott Transition in High Magnetic Fields Probed by Coherent Terahertz Spectroscopy

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