We present a proof of concept for a spectrally selective thermal midIR source based on nanopatterned graphene (NPG) with a typical mobility of CVDgrown graphene (up to 3000
The emergence of saddlepoint Van Hove singularities (VHSs) in the density of states, accompanied by a change in Fermi surface topology, Lifshitz transition, constitutes an ideal ground for the emergence of different electronic phenomena, such as superconductivity, pseudogap, magnetism, and density waves. However, in most materials the Fermi level,
 Publication Date:
 NSFPAR ID:
 10153797
 Journal Name:
 Nature Communications
 Volume:
 10
 Issue:
 1
 ISSN:
 20411723
 Publisher:
 Nature Publishing Group
 Sponsoring Org:
 National Science Foundation
More Like this

Abstract ), ensuring scalability to large areas. For that, we solve the electrostatic problem of a conducting hyperboloid with an elliptical wormhole in the presence of an$$\hbox {cm}^2\,\hbox {V}^{1}\,\hbox {s}^{1}$$ ${\text{cm}}^{2}\phantom{\rule{0ex}{0ex}}{\text{V}}^{1}\phantom{\rule{0ex}{0ex}}{\text{s}}^{1}$inplane electric field. The localized surface plasmons (LSPs) on the NPG sheet, partially hybridized with graphene phonons and surface phonons of the neighboring materials, allow for the control and tuning of the thermal emission spectrum in the wavelength regime from to 12$$\lambda =3$$ $\lambda =3$ m by adjusting the size of and distance between the circular holes in a hexagonal or square lattice structure. Most importantly, the LSPs along with an optical cavity increase the emittance of graphene from about 2.3% for pristine graphene to 80% for NPG, thereby outperforming stateoftheart pristine graphene light sources operating in the nearinfrared by at least a factor of 100. According to our COMSOL calculations, a maximum emission power per area of$$\upmu$$ $\mu $ W/$$11\times 10^3$$ $11\times {10}^{3}$ at$$\hbox {m}^2$$ ${\text{m}}^{2}$ K for a bias voltage of$$T=2000$$ $T=2000$ V is achieved by controlling the temperature of the hot electrons through the Joule heating. By generalizing Planck’s theory to any grey body and derivingmore »$$V=23$$ $V=23$ 
Abstract Kondo insulators are expected to transform into metals under a sufficiently strong magnetic field. The closure of the insulating gap stems from the coupling of a magnetic field to the electron spin, yet the required strength of the magnetic field–typically of order 100 T–means that very little is known about this insulatormetal transition. Here we show that Ce
Bi$${}_{3}$$ ${}_{3}$ Pd$${}_{4}$$ ${}_{4}$ , owing to its fortuitously small gap, provides an ideal Kondo insulator for this investigation. A metallic Fermi liquid state is established above a critical magnetic field of only$${}_{3}$$ ${}_{3}$ 11 T. A peak in the strength of electronic correlations near$${B}_{{\rm{c}}}\approx$$ ${B}_{c}\approx $ , which is evident in transport and susceptibility measurements, suggests that Ce$${B}_{{\rm{c}}}$$ ${B}_{c}$ Bi$${}_{3}$$ ${}_{3}$ Pd$${}_{4}$$ ${}_{4}$ may exhibit quantum criticality analogous to that reported in Kondo insulators under pressure. Metamagnetism and the breakdown of the Kondo coupling are also discussed.$${}_{3}$$ ${}_{3}$ 
Abstract The interplay between charge transfer and electronic disorder in transitionmetal dichalcogenide multilayers gives rise to superconductive coupling driven by proximity enhancement, tunneling and superconducting fluctuations, of a yet unwieldy variety. Artificial spacer layers introduced with atomic precision change the density of states by charge transfer. Here, we tune the superconductive coupling between
monolayers from proximityenhanced to tunnelingdominated. We correlate normal and superconducting properties in $\text{NbS}{\text{e}}_{\text{2}}$ tailored multilayers with varying SnSe layer thickness ( ${\left[{\left(\text{SnSe}\right)}_{1+\delta}\right]}_{m}{\left[\text{NbS}{\text{e}}_{\text{2}}\right]}_{1}$ ). From highfield magnetotransport the critical fields yield Ginzburg–Landau coherence lengths with an increase of $m=115$ crossplane ( $140\mathrm{\%}$ ), trending towards twodimensional superconductivity for $m=19$ . We show crossovers between three regimes: metallic with proximityenhanced coupling ( $m>9$ ), disorderedmetallic with intermediate coupling ( $m=14$ ) and insulating with Josephson tunneling ( $m=59$ ). Our results demonstrate that stacking metal mono and dichalcogenides allows to convert a metal/superconductor into an insulator/superconductor system, prospecting the control of twodimensional superconductivity in embedded layers. $m>9$ 
Abstract The proximity of many strongly correlated superconductors to densitywave or nematic order has led to an extensive search for fingerprints of pairing mediated by dynamical quantumcritical (QC) fluctuations of the corresponding order parameter. Here we study anisotropic
s wave superconductivity induced by anisotropic QC dynamical nematic fluctuations. We solve the nonlinear gap equation for the pairing gap and show that its angular dependence strongly varies below$$\Delta (\theta ,{\omega }_{m})$$ $\Delta \left(\theta ,{\omega}_{m}\right)$ . We show that this variation is a signature of QC pairing and comes about because there are multiple$${T}_{{\rm{c}}}$$ ${T}_{c}$s wave pairing instabilities with closely spaced transition temperatures . Taken alone, each instability would produce a gap$${T}_{{\rm{c}},n}$$ ${T}_{c,n}$ that changes sign$$\Delta (\theta ,{\omega }_{m})$$ $\Delta \left(\theta ,{\omega}_{m}\right)$ times along the Fermi surface. We show that the equilibrium gap$$8n$$ $8n$ is a superposition of multiple components that are nonlinearly induced below the actual$$\Delta (\theta ,{\omega }_{m})$$ $\Delta (\theta ,{\omega}_{m})$ , and get resonantly enhanced at$${T}_{{\rm{c}}}={T}_{{\rm{c}},0}$$ ${T}_{c}={T}_{c,0}$ . This gives rise to strong temperature variation of the angular dependence of$$T={T}_{{\rm{c}},n}\ <\ {T}_{{\rm{c}}}$$ $T={T}_{c,n}\phantom{\rule{0ex}{0ex}}<\phantom{\rule{0ex}{0ex}}{T}_{c}$ . This variation progressively disappears away from a QC point.$$\Delta (\theta ,{\omega }_{m})$$ $\Delta \left(\theta ,{\omega}_{m}\right)$ 
Abstract We construct an example of a group
for a finite abelian group$$G = \mathbb {Z}^2 \times G_0$$ $G={Z}^{2}\times {G}_{0}$ , a subset$$G_0$$ ${G}_{0}$E of , and two finite subsets$$G_0$$ ${G}_{0}$ of$$F_1,F_2$$ ${F}_{1},{F}_{2}$G , such that it is undecidable in ZFC whether can be tiled by translations of$$\mathbb {Z}^2\times E$$ ${Z}^{2}\times E$ . In particular, this implies that this tiling problem is$$F_1,F_2$$ ${F}_{1},{F}_{2}$aperiodic , in the sense that (in the standard universe of ZFC) there exist translational tilings ofE by the tiles , but no periodic tilings. Previously, such aperiodic or undecidable translational tilings were only constructed for sets of eleven or more tiles (mostly in$$F_1,F_2$$ ${F}_{1},{F}_{2}$ ). A similar construction also applies for$$\mathbb {Z}^2$$ ${Z}^{2}$ for sufficiently large$$G=\mathbb {Z}^d$$ $G={Z}^{d}$d . If one allows the group to be nonabelian, a variant of the construction produces an undecidable translational tiling with only one tile$$G_0$$ ${G}_{0}$F . The argument proceeds by first observing that a single tiling equation is able to encode an arbitrary system of tiling equations, which in turn can encode an arbitrary system of certain functional equations once one has two or more tiles. In particular, one can use two tiles to encode tiling problems for an arbitrary number of tiles.