Anomalously Large Resistance at the Charge Neutrality Point in a Zero-Gap InAs/GaSb Bilayer


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 (similar to 500 k Omega) 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 Kand 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.


Includes supplementary material


Quantum-wells, Semiconductos, Electron transport, Indium arsenide, Gallium antimonide

US Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division at Sandia, MINECO and FEDER MAT2013-46308-C2-1-R and MAT2016-75955-C2-2-R; Junta de Castilla y León SA045U16 at University of Salamanca; US Department of Energy (Grant No. DE-FG02-07ER46451); US Department of Energy, Office of Basic Energy Sciences user facility at Los Alamos National Laboratory (Contract No. DEAC52-06NA25396), and Sandia National Laboratories (Contract No. DE-AC04-94AL85000).


CC BY 3.0 (Attribution), ©2018 The Authors