Tracking Intrinsic Non-Hermitian Skin Effect in Lossy Lattices

Non-Hermitian skin effect (NHSE), characterized by a majority of eigenstates localized at open boundaries, is one of the most iconic phenomena in non-Hermitian lattices. Despite notable experimental studies implemented, most of them witness only certain signs of the NHSE rather than the intrinsic exponential localization inherent in eigenstates, owing to the ubiquitous and inevitable background loss. Even worse, the experimental observation of the NHSE would be completely obscured in highly lossy cases. Here, we theoretically propose a dual test approach to eliminate the destructive loss effect and track the intrinsic NHSE that is essentially irrelevant to background loss. Experimentally, the effectiveness of this approach is precisely validated by one- and two-dimensional non-Hermitian acoustic lattices. Our study sheds new light on the previously untapped intrinsic aspect of the NHSE, which is of particular significance in non-Hermitian topological physics

Direction dependent switching of carrier-type enabled by Fermi surface geometry

While charge carriers can typically be designated as either electron- or hole- type, depending on the sign of the Hall coefficient, some materials defy this straightforward classification. Here we find that LaRh$_6$Ge$_4$ goes beyond this dichotomy, where the Hall resistivity is electron-like for magnetic fields along the $c$-axis but hole-like in the basal plane. Together with first-principles calculations, we show that this direction-dependent switching of the carrier type arises within a single band, where the special geometry leads to charge carriers on the same Fermi surface orbiting as electrons along some directions, but holes along others. The relationship between the Fermi surface geometry and occurrence of a Hall sign reversal is further generalized by considering tight-binding model calculations, which show that this type of Fermi surface corresponds to a more robust means of realizing this phenomenon, suggesting an important route for tailoring direction dependent properties for advanced electronic device applications.Comment: 7 pages, 5 figure

A Family of Lanthanide Noncentrosymmetric Superconductors La4_4TXTX (TT = Ru, Rh, Ir; XX = Al, In)

We report the discovery of superconductivity in a series of noncentrosymmetric compounds La$_4$$TX$ ($T$ = Ru, Rh, Ir; $X$ = Al, In), which have a cubic crystal structure with space group $F\bar{4}3m$. La$_4$RuAl, La$_4$RhAl, La$_4$IrAl, La$_4$RuIn and La$_4$IrIn exhibit bulk superconducting transitions with critical temperatures $T_c$ of 1.77 K, 3.05 K, 1.54 K, 0.58 K and 0.93 K, respectively. The specific heat of the La$_4$$T$Al compounds are consistent with an $s$-wave model with a fully open superconducting gap. In all cases, the upper critical fields are well described by the Werthamer-Helfand-Hohenberg model, and the values are well below the Pauli limit, indicating that orbital limiting is the dominant pair-breaking mechanism. Density functional theory (DFT) calculations reveal that the degree of band splitting by the antisymmetric spin-orbit coupling (ASOC) shows considerable variation between the different compounds. This indicates that the strength of the ASOC is highly tunable across this series of superconductors, suggesting that these are good candidates for examining the relationship between the ASOC and superconducting properties in noncentrosymmetric superconductors.Comment: 10 pages, 7 figure

Effect of Clozapine on Anti-N-Methyl-D-Aspartate Receptor Encephalitis With Psychiatric Symptoms: A Series of Three Cases

The main clinical manifestations of anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis are acute or subacute seizures, cognition impairment, and psychiatric symptoms. Nowadays, the scheme of antipsychotic therapy for this disease has not been established. This study reports three cases of anti-NMDAR encephalitis with psychiatric symptoms. The anti-NMDAR antibodies in cerebrospinal fluid (CSF) and serum were positive. The psychiatric symptoms still existed after intravenous immunoglobulin (IVIG) treatment; thus, clozapine was used for antipsychotic therapy. Case 1 was a 37-year-old man who suffered from bad mood and suicide behaviors for 1 month. Hallucination and delusion still existed after IVIG treatment and hormone therapy, and the symptoms were relieved when given clozapine for 12 months. Case 2 was a 28-year-old man who was admitted to our hospital due to injuring other people and destructive behaviors for 2 days. He showed irritability, bad temper, declined cognition, and severe delusion of persecution after IVIG treatment and hormone therapy, but the psychiatric symptoms disappeared when given clozapine for 3 months. Case 3 was a 23-year-old man who suffered from headache and babbing for 7 days. Symptoms such as irritability, bad temper, babbing, and injuring other people still existed after IVIG treatment and hormone therapy, but they disappeared when given clozapine for 2 months. Therefore, we suggest that during the treatment of anti-NMDAR encephalitis with psychiatric symptoms, if the anti-NMDAR antibodies in CSF and serum were positive, and psychiatric symptoms could not be controlled after IVIG and hormone therapy, clozapine may work

Electronic band reconstruction across the insulator-metal transition in colossal magnetoresistive EuCd2P2

While colossal magnetoresistance (CMR) in Eu-based compounds is often associated with strong spin-carrier interactions, the underlying reconstruction of the electronic bands is much less understood from spectroscopic experiments. Here using angle-resolved photoemission, we directly observe an electronic band reconstruction across the insulator-metal (and magnetic) transition in the recently discovered CMR compound EuCd2P2. This transition is manifested by a large magnetic band splitting associated with the magnetic order, as well as unusual energy shifts of the valence bands: both the large ordered moment of Eu and carrier localization in the paramagnetic phase are crucial. Our results provide spectroscopic evidence for an electronic structure reconstruction underlying the enormous CMR observed in EuCd2P2, which could be important for understanding Eu-based CMR materials, as well as designing CMR materials based on large-moment rare-earth magnets.Comment: 6 pages, 4 figure

An ultralight, supercompressible, superhydrophobic and multifunctional carbon aerogel with a specially designed structure

Abstract(#br)Compressible and ultralight carbon aerogels are attractive due to its compressibility, elasticity and conductivity. However, it is still a great challenge to enrich the properties of carbon aerogel to meet various requirements. Herein, we report an untralight, supercompressible, fatigue resistant, superhydrophobic and fire-resistant and multifunctional CNF-GO/glucose-kaolin carbon aerogel (C-NGGK) carbon aerogel. To achieve such excellent performances, calcined GO, CNFs, glucose and kaolin are used for forming low-density and continuous wave-shape rGO layers, reinforcing the mechanical strength of carbon layers, realizing superelasticity and fatigue resistance and resulting in a superhydrophobic surface for C-NGGK, respectively. The as-prepared C-NGGK demonstrates excellent superhydrophobicity with the water contact angle (WCA) of 124.9°, and the absorption efficiency of the C-NGGK samples for different oils and organic solvents are 75–255 times their own weight. These advantages show that the C-NGGK can be an ideal candidate for oil/water separation. In addition, there is also the prospect to be used for pressure sensors, while other potential applications include three-dimensional electrode materials for supercapacitors and batteries, catalyst carriers and various wearable devices

Intrinsic Electronic Structure and Nodeless Superconducting Gap of YBa2Cu3O7−δ\mathrm{YBa_{2} Cu_{3} O_{7-\delta} } Observed by Spatially-Resolved Laser-Based Angle Resolved Photoemission Spectroscopy

The spatially-resolved laser-based high resolution ARPES measurements have been performed on the optimally-doped $\mathrm{YBa_{2} Cu_{3} O_{7-\delta} }$ (Y123) superconductor. For the first time, we found the region from the cleaved surface that reveals clear bulk electronic properties. The intrinsic Fermi surface and band structures of Y123 are observed. The Fermi surface-dependent and momentum-dependent superconducting gap is determined which is nodeless and consistent with the d+is gap form

Examining the Antecedents of Brand Engagement of Tourists Based on the Theory of Value Co-Creation

Tourist engagement in marketing activities for destinations has been seen as a new driving force for the sustainable development of such destinations and as an effective way to improve their brand equity. Based on the theory of value co-creation and the theory of consumer-based brand equity for destinations, this paper examines the antecedents of brand engagement and the causal paths among them and compares the estimated values of different paths with brand image, brand awareness, and brand quality as the independent variables; brand value and brand trust as the mediating variables; and brand engagement as the dependent variable, taking Shandong Province as an example. The final results show that brand image, brand awareness, and brand quality are all key antecedents of brand engagement; however, they play different roles. The total effect of brand quality is the largest, the total effect of brand awareness follows, and the total effect of brand image is the smallest. Furthermore, the mediating effect of brand value is larger than the mediating effect of brand trust. The results provide empirical support for promoting the management of brand equity for similar destinations and encouraging tourists to participate in value co-creation activities