Even-odd correlations in capacitance fluctuations of quantum dots

We investigate effects of short range interactions on the addition spectra of quantum dots using a disordered Hubbard model. A correlation function \cS(q) is defined on the inverse compressibility versus filling data, and computed numerically for small lattices. Two regimes of interaction strength are identified: the even/odd fluctuations regime typical of Fermi liquid ground states, and a regime of structureless \cS(q) at strong interactions. We propose to understand the latter regime in terms of magnetically correlated localized spins.Comment: 3 pages, Revtex, Without figure

Wigs, disguises and child's play : solidarity in teacher education

It is generally acknowledged that much contemporary education takes place within a dominant audit culture, in which accountability becomes a powerful driver of educational practices. In this culture both pupils and teachers risk being configured as a means to an assessment and target-driven end: pupils are schooled within a particular paradigm of education. The article discusses some ethical issues raised by such schooling, particularly the tensions arising for teachers, and by implication, teacher educators who prepare and support teachers for work in situations where vocational aims and beliefs may be in in conflict with instrumentalist aims. The article offers De Certeau’s concept of ‘la perruque’ to suggest an opening to playful engagement for human ends in education, as a way of contending with and managing the tensions generated. I use the concept to recover a concept of solidarity for teacher educators and teachers to enable ethical teaching in difficult times

The structure and correlates of vegan stereotypes

Previous research suggests that people hold both positive and negative stereotypes of vegans, but little is known about the specific content of those stereotypes. In two studies (total N = 2,027), we identified the structure of meat-eaters’ stereotypes of vegans and developed a scale to measure them. Stereotypes of vegans assorted into three positive (compassionate, healthy, and self-disciplined) and three negative (unconventional, condescending, and unhealthy) dimensions. Meat-eaters perceived vegans more positively when they understood their motivations for their diet, were familiar with vegans, and shared their concerns for the environment. In contrast, meat-eaters who perceived vegans more negatively were more conservative, had a strong meat-eating identity, and were highly motivated to eat meat. Whereas most attitudes predicted overall positive and negative evaluations of vegans, some predicted specific stereotypes of vegans. This model and scale provide a foundation for vegan stereotype research and for improving intergroup relations between meat-eaters and vegans

Higgs lepton flavour violation: UV completions and connection to neutrino masses

We study lepton violating Higgs (HLFV) decays, first from the effective field theory (EFT) point of view, and then analysing the different high-energy realizations of the operators of the EFT, highlighting the most promising models. We argue why two Higgs doublet models can have a BR(h → τ μ) ∼ 0.01, and why this rate is suppressed in all other realizations including vector-like leptons. We further discuss HLFV in the context of neutrino mass models: in most cases it is generated at one loop giving always BR(h → τ μ) < 10−4 and typically much less, which is beyond experimental reach. However, both the Zee model and extended left-right symmetric models contain extra SU(2) doublets coupled to leptons and could in principle account for the observed excess, with interesting connections between HLFV and neutrino parameters

Conformal High-K Dielectric Coating of Suspended Single-Walled Carbon Nanotubes by Atomic Layer Deposition

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6723932/As one of the highest mobility semiconductor materials, carbon nanotubes (CNTs) have been extensively studied for use in field effect transistors (FETs). To fabricate surround-gate FETs— which offer the best switching performance—deposition of conformal, weakly-interacting dielectric layers is necessary. This is challenging due to the chemically inert surface of CNTs and a lack of nucleation sites—especially for defect-free CNTs. As a result, a technique that enables integration of uniform high-k dielectrics, while preserving the CNT’s exceptional properties is required. In this work, we show a method that enables conformal atomic layer deposition (ALD) of high-k dielectrics on defect-free CNTs. By depositing a thin Ti metal film, followed by oxidation to TiO2 under ambient conditions, a nucleation layer is formed for subsequent ALD deposition of Al2O3. The technique is easy to implement and is VLSI-compatible. We show that the ALD coatings are uniform, continuous and conformal, and Raman spectroscopy reveals that the technique does not induce defects in the CNT. The resulting bilayer TiO2/Al2O3 thin-film shows an improved dielectric constant of 21.7 and an equivalent oxide thickness of 2.7 nm. The electrical properties of back-gated and top-gated devices fabricated using this method are presented

Tribological behavior of few-nanometer-thick MoS2 prepared by low-temperature conversion of atomic layer deposited MoOx films

Molybdenum disulfide (MoS2) is a popular lamellar material with desirable properties who's form, and function can vary widely, from particles to monolayer/μm thick films and applications in semiconductors to aerospace lubricants and many more. Physical vapor deposition (PVD) is commonly used to produce dense, conformal micron thick MoS2 coatings, but lacks the ability to coat more complex geometries due to line-of-sight constraints and typically exhibit amorphous or nanocrystalline microstructures. Atomic layer deposition (ALD) has also been employed to deposit monolayer to 10's of nanometers thick lamellar solids like MoS2 &amp; WS2 in transistor, sensors or electrocatalyst applications but not commonly for applications as solid lubricants in aerospace like their PVD counterparts. While recent work has shown that ALD MoS2 can exhibit favorable microstructures for solid lubricant applications and allows for non-line of sight deposition on complex geometries, it has not been widely adopted due to high deposition temperatures (&gt;500 °C) that can lead to softening of steel substrates. In this work, we show one of the first applications highlighting the use of ultra-thin (5–10 nm) low temperature (∼250 °C) MoS2 coatings as a promising solid lubricant for macroscale mechanical interfaces. Post-deposition chemical conversion of ALD MoOx to MoS2 by annealing in H2S at temperatures ranging from 200 to 550 °C resulted in highly-ordered basally-oriented surface microstructures. The results from this work suggest that converted-ALD MoS2 coatings can serve as viable solid lubricants for aerospace applications requiring low-temperature processing, including those with complex geometries