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We report a technique for fabricating suspended structures using tilted electron beam lithography. This technique enables the formation of beveled anchor profiles, which significantly increase structural integrity compared to previous techniques. We demonstrate the technique by fabricating a suspended top gate over a graphene device, achieving a breakdown electric field of up to 1.5 V/nm, and induced carrier densities of ∼ 7 × 1012 cm−2, both representing more than 10-fold increase from previous methods. This technique provides a pathway to robust suspended electronic structures capable of withstanding large electrostatic forces common in two-dimensional material systems and nanoelectromechanical devices. 

The superconducting order parameter at the KTaO3 interfaces and its dependence on interface orientation remains a subject of debate. The superconductivity at these interfaces exhibits strong resilience against in-plane magnetic field and violates Pauli limit. The interface orientation dependence of critical field and violation of Pauli limit, however, have not been investigated. To address this problem, we grew epitaxial LaMnO3/KTaO3 heterostructures using molecular beam epitaxy. We show that superconductivity is extremely robust against the in-plane magnetic field. The critical field to the Pauli limiting field coincides with the (111) interfaces for the same carrier density. This suggests that the orientation of the surface does not play a critical role in determining the ratio, despite the strong impact on the critical temperature. These results offer opportunities to engineer superconductors which are resilient against magnetic field. 

Two-dimensional (2D) materials have drawn immense interests in scientific and technological communities, owing to their extraordinary properties and their tunability by gating, proximity, strain and external fields. For electronic applications, an ideal 2D material would have high mobility, air stability, sizable band gap, and be compatible with large scale synthesis. Here we demonstrate air stable field effect transistors using atomically thin few-layer PdSe2 sheets that are sandwiched between hexagonal BN (hBN), with large saturation current > 350 μA/μm, and high field effect mobilities of ~ 700 and 10,000 cm2/Vs at 300 K and 2 K, respectively. At low temperatures, magnetotransport studies reveal unique octets in quantum oscillations that persist at all densities, arising from 2-fold spin and 4-fold valley degeneracies, which can be broken by in-plane and out-of-plane magnetic fields toward quantum Hall spin and orbital ferromagnetism.