Epitaxial superconductor-semiconductor two-dimensional systems for superconducting quantum circuits

Abstract

Qubits on solid state devices could potentially provide the rapid control necessary for developing scalable quantum information processors. Materials innovation and design breakthroughs have increased functionality and coherence of qubits substantially over the past two decades. Here, we show by improving interface between InAs as a semiconductor and Al as a superconductor, one can reliably fabricate voltage-controlled Josephson junction field effect transistor (JJ-FET) that can be used as tunable qubits, resonators, and coupler switches. We find that bandgap engineering is crucial in realizing a two-dimensional electron gas near the surface. In addition, we show how the coupling between the semiconductor layer and the superconducting contacts can affect qubit properties. We present the anharmonicity and coupling strengths from one and two-photon absorption in a quantum two level system fabricated with a JJ-FET.

Protected hybrid superconducting qubit in an array of gate-tunable Josephson interferometers

“…In the long-array limit, a giant-spin model yielded a quantum phase transition as function of flux offset between protected and unprotected regimes. The construction of interferometer array protected qubits can be realized using existing semiconductor-superconductor hybrid materials based on semiconductor nanowires [19] or twodimensional heterostructures [28,45,46]. where ñ and ñg are vectors that contain the Cooper pair number operators and the offset charges of the N +1 superconducting islands, and φ is the vector of phase operators.…”

Gate-Tunable Transmon Using Selective-Area-Grown Superconductor-Semiconductor Hybrid Structures on Silicon

“…Second, the qubit capacitor, readout and control components can be fabricated directly on the high resistivity silicon substrate with low dielectric loss [13], similar to VLS-nanowire gatemons [2]. Similar experiments implemented on III-V substrates report a resonator quality factor of 6 × 10 4 [4] or lower [4,[14][15][16] and qubit relaxation times up to a few microseconds [4]. The main source of losses on III-V substrates can be explained by the piezoelectric photon-phonon coupling in these materials [14,15].…”

Two-Dimensional Dielectrics for Future Electronics: Hexagonal Boron Nitride, Oxyhalides, Transition-Metal Nitride Halides, and Beyond

“…Two-dimensional (2D) van der Waals (vdW) materials have received an enormous amount of attention in the research community, with prominent envisioned applications in the fields of nanoelectronics, optoelectronics, spintronics, quantum information, and thermoelectric devices. − At the heart of nanoelectronic technology, we find the metal-oxide-semiconductor field-effect transistor (MOSFET), which consists of a source and a drain connected by a channel. A gate controls the electrostatic potential in the channel, but to avoid leakage currents, a befitting dielectric is critically required between the gate and the channel.…”