Magnetotransport measurements on InAs-GaSb quantum wells with the application of hydrostatic pressure

Structural, morphological and magnetotransport properties of composite semiconducting and semimetallic InAs/GaSb superlattice structure

“…It has been reported that the InAs/GaSb SL system can exhibit a transition from semiconducting to semimetallic when the InAs layer thickness exceeds 8.5 nm. 19 However, both theoretical and experimental investigations demonstrated the formation of a hybridization minigap even in the semimetallic InAs/GaSb system. [14][15][16] The InAs layer thicknesses designed for in this study were selected to be 7.5 nm in the short-period SL structure (such that it displays semiconducting behavior with E G 4 0), and 15 nm in the longperiod SL structure (such that it displays semimetallic behavior with E G r 0).…”

“…It should be noted that whereas the previous calculations do not consider external effects on the SL band structure, it is wellknown that the formation of a minigap in InAs/GaSb heterostructures can be sensitive to external factors, e.g., applied B [15][16][17]34 or hydrostatic pressure. 19 Due to the magnitude of the minigap, it is therefore necessary to examine the impact of B on the formation or dissolution of the anticrossing gap or hybridization minigap. In order to properly account for the effect of B applied normally to the plane of the sample on the band structure, we have used the standard Peierls substitution in the Hamiltonian.…”

“…10a and its inset demonstrate that the negative magnetoresistance of R XX around B E 0 T also abruptly arises with lowering T below 5 K. It is hence plausible that the same effect underlies both the rise in R XX for T o 5 K and the development of the striking magnetoresistance. Tentatively the intricate magnetoresistance in R XX and R YY and the dependence of transport and magnetotransport on T can be tied to the observation [15][16][17]19,34,47 that anticrossing gaps and positive gaps, 15,[38][39][40] as well as several carrier populations with the potential to contribute to conductance, exist in InAs/ GaSb heterostructures and are sensitive to external B. [15][16][17]40 In the present work however, the complicated nature of the magnetoresistance, the abrupt dependence on T and the identification of at least two carrier populations defy a rigorous tie to theory.…”

“…Moreover, the presence of a minigap in the InAs/GaSb system has been responsible for several observations of magnetoresistance. [15][16][17] This suggests the possibility of tuning the electronic and optical properties of the InAs/ GaSb system by: (i) varying the periodicity of the SL and thereby the minigap formation; [15][16][17][18] (ii) applying a hydrostatic pressure in order to modify the conduction-valence band overlap; 19 (iii) adding indium (In) to the GaSb layers (i.e., InGaSb), thus further increasing the band overlap; 20 (iv) utilizing different surface orientations so as to leverage their intrinsic dipole effects and further increase the band overlap, 19,21 or (v) exploiting monolayer atomic stacking sequences at the InAs/GaSb heterointerfaces to change the carrier density and band overlap. It has also been reported that the InAs/GaSb interface can be designed to exhibit either an InSb-like interface or both InSb-and GaAs-like interfaces in GaSb/InSb or GaSb/GaAs-like/ InAs/InSb-like/GaSb SL structures.…”

Current-driven breakdown of the quantized Hall states of a broken-gap 2D electron–hole system

“…In this paper we describe experimental studies of the current driven breakdown of the quantum Hall effect in an InAs/GaSb-based electron-hole system. InAs/GaSb is a broken-gap system with the ability to possess both electrons and holes in equilibrium through intrinsic charge transfer [14][15][16][17][18]. Quantum Hall plateaux in an InAs/GaSb-based electron-hole system [19] occur at Hall resistance values corresponding to the difference in the occupancies of the electron and hole Landau levels.…”