Publications

Anomalously large resistance at the charge neutrality point in a zero-gap InAs/GaSb bilayer

Yu, W.; Clericò, V.; Fuentevilla, C.H.; Shi, X.; Jiang, Y.; Saha, D.; Lou, W.K.; Chang, K.; Huang, D.H.; Gumbs, G.; Smirnov, D.; Stanton, C.J.; Jiang, Z.; Bellani, V.; Meziani, Y.; Diez, E.; Pan, Wei P.; Hawkins, Samuel D.; Klem, John F.

We report here our recent electron transport results in spatially separated two-dimensional electron and hole gases with nominally degenerate energy subbands, realized in an InAs(10 nm)/GaSb(5 nm) coupled quantum well. We observe a narrow and intense maximum (∼500 kΩ) in the four-terminal resistivity in the charge neutrality region, separating the electron-like and hole-like regimes, with a strong activated temperature dependence above T = 7 K and perfect stability against quantizing magnetic fields. We discuss several mechanisms for that unexpectedly large resistance in this zero-gap semi-metal system including the formation of an excitonic insulator state.