High mobility back-gated InAs/GaSb double quantum well grown on GaSb substrate

Nguyen, Binh‐Minh; Yi, Wei; Noah, Ramsey; Thorp, J. S.; Sokolich, M.

doi:10.1063/1.4906589

Cited by 17 publications

(20 citation statements)

References 34 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Devices used in this work were grown and fabricated using the same procedure as the previous study [12]. The only difference is that the wafer was grown in a different growth campaign, and resulted in slightly lower mobility, 200 000 cm 2 =Vs in this material, in comparison with 500 000 cm 2 =Vs in our previously reported results [12], both at N s ¼ 10 12 cm −2 .…”

mentioning

confidence: 99%

“…Without a complete 2D phase diagram, the inverted regime can only be indirectly inferred, e.g., based on the resistance behavior under in-plane [3,10] or out of plane [10,11] magnetic field. It was not until recently that the complete 2D phase diagram was experimentally demonstrated [9] with the use of high mobility materials and efficient back gate coupling [12].…”

mentioning

confidence: 99%

See 1 more Smart Citation

Decoupling Edge Versus Bulk Conductance in the Trivial Regime of anInAs/GaSbDouble Quantum Well Using Corbino Ring Geometry

et al. 2016

Self Cite

View full text Add to dashboard Cite

A Corbino ring geometry is utilized to analyze edge and bulk conductance of InAs/GaSb quantum well structures. We show that edge conductance exists in the trivial regime of this theoretically-predicted topological system with a temperature insensitive linear resistivity per unit length in the range of 2 k/m. A resistor network model of the device is developed to decouple the edge conductance from the bulk conductance, providing a quantitative technique to further investigate the nature of this trivial edge conductance, conclusively identified here as being of n-type.

show abstract

mentioning

confidence: 99%

mentioning

confidence: 99%

Decoupling Edge Versus Bulk Conductance in the Trivial Regime of anInAs/GaSbDouble Quantum Well Using Corbino Ring Geometry

et al. 2016

Self Cite

View full text Add to dashboard Cite

show abstract

“…Importantly, the GaSb substrate is lattice matched with the subsequent layers, which eliminates the requirement of a thick buffer layer compared to the commonly used GaAs substrate and therefore enables a strong coupling between the back gate and quantum wells. Furthermore, for such choice of substrate, strain and the amount of dislocations are reduced, resulting in record values of carrier mobility for this type of DQWs [24,25]. The Hall bars of 100 by 20 μm used in our measurements are chemically wet etched [inset of Fig.…”

mentioning

confidence: 99%

“…Our heterostructure was grown by molecular-beam epitaxy [24,25]. A 100 nm buffer layer was first grown on a doped GaSb substrate, followed by a 50 nm AlSb bottom barrier.…”

mentioning

confidence: 99%

Electric and Magnetic Tuning Between the Trivial and Topological Phases in InAs/GaSb Double Quantum Wells

et al. 2015

Self Cite

View full text Add to dashboard Cite

Among the theoretically predicted two-dimensional topological insulators, InAs=GaSb double quantum wells (DQWs) have a unique double-layered structure with electron and hole gases separated in two layers, which enables tuning of the band alignment via electric and magnetic fields. However, the rich trivialtopological phase diagram has yet to be experimentally explored. We present an in situ and continuous tuning between the trivial and topological insulating phases in InAs=GaSb DQWs through electrical dual gating. Furthermore, we show that an in-plane magnetic field shifts the electron and hole bands relatively to each other in momentum space, functioning as a powerful tool to discriminate between the topologically distinct states. DOI: 10.1103/PhysRevLett.115.036803 PACS numbers: 73.21.Fg, 71.30.+h, 72.80.Ey Two-dimensional topological insulators (2DTIs), known also as quantum spin Hall insulators, are a novel class of materials characterized by an insulating bulk and gapless helical edges [1][2][3][4]. Double quantum wells (DQWs) of indium arsenide and gallium antimonide (InAs=GaSb) have a unique type-II broken gap band alignment and are especially interesting since the electron and hole gases that form a topological band structure are spatially separated [5][6][7][8]. For the appropriate layer thicknesses, the top of the hole band in GaSb lies above the bottom of the electron band in InAs; hence, for small momentum (around k ¼ 0) the band structure is inverted. At the crossing point (k cross ) of the two bands, coupling of the electrons and holes opens up a bulk hybridization gap [9][10][11][12][13][14][15][16] with gapless helical edge modes [5]. The size of the gap is determined by both k cross and the overlap of the electron and hole wave functions [17]. Because of the spatial separation of the two gases, electric and magnetic fields can induce relative shifts of the bands in energy and momentum [10,18,19], respectively. By controlling such shifts, it is possible to in situ tune between the trivial and topological insulating phases, which is the key advantage of InAs=GaSb compared to the other known 2DTIs [5,[20][21][22].Here, for the first time, we map out the full phase diagram of the InAs=GaSb DQWs by independent control of the Fermi level and the band alignment through electric dual gating. In particular, we observe the phase transition between the trivial insulator (normal gap) and topological insulator (hybridization gap). Moreover, the evolution of the resistance for in-plane magnetic fields is different in the two distinct phases, consistent with the fact that one is trivial, and the other topological.In InAs=GaSb DQWs, the band alignment can be controlled by top and back gate electrodes [5,18] [see the structure shown in Fig. 1(a) ]. The two gates control the perpendicular electric field E z , which shifts the electron and the hole bands relatively to each other in energy by ΔE ¼ eE z hzi (hzi is the average separation of the electron and hole gases), and the position of the Fermi level E F . ...

show abstract

“…With these insights about InAs in mind we now turn to the discussion of InAs/GaSb double quantum well structures, which contain a hybridized electron-hole system [27][28][29][30][31][32]. Despite multiple affirmations of edge conduction in the inverted regime of InAs/GaSb [8][9][10][11][12][13][14], a careful analysis of the various possible contributions to edge conduction is missing.…”

Section: Comparison To Transport In Inas/gasbmentioning

confidence: 99%

Edge transport in InAs and InAs/GaSb quantum wells

et al. 2017

View full text Add to dashboard Cite

We investigate low-temperature transport through single InAs quantum wells and broken-gap InAs/GaSb double quantum wells. Non-local measurements in the regime beyond bulk pinch-off confirm the presence of edge conduction in InAs quantum wells. The edge resistivity of 1-2 kΩ/µm is of the same order of magnitude as edge resistivities measured in the InAs/GaSb double quantum well system. Measurements in tilted magnetic field suggests an anisotropy of the conducting regions at the edges with a larger extent in the plane of the sample than normal to it. Finger gate samples on both material systems shine light on the length dependence of the edge resistance with the intent to unravel the nature of edge conduction in InAs/GaSb coupled quantum wells.

show abstract

High mobility back-gated InAs/GaSb double quantum well grown on GaSb substrate

Cited by 17 publications

References 34 publications

Decoupling Edge Versus Bulk Conductance in the Trivial Regime of anInAs/GaSbDouble Quantum Well Using Corbino Ring Geometry

Decoupling Edge Versus Bulk Conductance in the Trivial Regime of anInAs/GaSbDouble Quantum Well Using Corbino Ring Geometry

Electric and Magnetic Tuning Between the Trivial and Topological Phases in InAs/GaSb Double Quantum Wells

Edge transport in InAs and InAs/GaSb quantum wells

Contact Info

Product

Resources

About