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Bilayer Graphene
Bilayer graphene is a material consisting of two layers of graphene. One of the first reports of bilayer graphene was in the seminal 2004 '' Science (journal), Science'' paper by Geim and colleagues, in which they described devices "which contained just one, two, or three atomic layers" Structure Bilayer graphene can exist in the AB, or Bernal-stacked form, where half of the atoms lie directly over the center of a hexagon in the lower graphene sheet, and half of the atoms lie over an atom, or, less commonly, in the AA form, in which the layers are exactly aligned. In Bernal stacked graphene, twin boundaries are common; transitioning from AB to BA stacking. Twisted layers, where one layer is rotated relative to the other, have also been extensively studied. Quantum Monte Carlo methods have been used to calculate the binding energies of AA- and AB-stacked bilayer graphene, which are 11.5(9) and 17.7(9) meV per atom, respectively. This is consistent with the observation that the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Graphene
Graphene () is an allotrope of carbon consisting of a single layer of atoms arranged in a hexagonal lattice nanostructure. "Carbon nanostructures for electromagnetic shielding applications", Mohammed Arif Poothanari, Sabu Thomas, et al., ''Industrial Applications of Nanomaterials'', 2019. "Carbon nanostructures include various low-dimensional allotropes of carbon including carbon black (CB), carbon fiber, carbon nanotubes (CNTs), fullerene, and graphene." The name is derived from "graphite" and the suffix -ene, reflecting the fact that the allotrope of carbon contains numerous double bonds. Each atom in a graphene sheet is connect ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harvard University
Harvard University is a private Ivy League research university in Cambridge, Massachusetts. Founded in 1636 as Harvard College and named for its first benefactor, the Puritan clergyman John Harvard, it is the oldest institution of higher learning in the United States and one of the most prestigious and highly ranked universities in the world. The university is composed of ten academic faculties plus Harvard Radcliffe Institute. The Faculty of Arts and Sciences offers study in a wide range of undergraduate and graduate academic disciplines, and other faculties offer only graduate degrees, including professional degrees. Harvard has three main campuses: the Cambridge campus centered on Harvard Yard; an adjoining campus immediately across Charles River in the Allston neighborhood of Boston; and the medical campus in Boston's Longwood Medical Area. Harvard's endowment is valued at $50.9 billion, making it the wealthiest academic institution in the world. Endow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The City University Of New York
, mottoeng = The education of free people is the hope of Mankind , budget = $3.6 billion , established = , type = Public university system , chancellor = Félix V. Matos Rodríguez , city = New York, New York , students = 275,000 , academic_staff = 19,568 , administrative_staff = 33,099 , affiliations = , campus = 25 campuses , coordinates = , website = , logo = City University of New York wordmark.svg , logo_size = 200px The City University of New York ( CUNY; , ) is the public university system of New York City. It is the largest urban university system in the United States, comprising 25 campuses: eleven senior colleges, seven community colleges and seven professional institutions. While its constituent colleges date back as far as 1847, CUNY ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lithium Ion Batteries
A lithium-ion or Li-ion battery is a type of rechargeable battery which uses the reversible reduction of lithium ions to store energy. It is the predominant battery type used in portable consumer electronics and electric vehicles. It also sees significant use for grid-scale energy storage and military and aerospace applications. Compared to other rechargeable battery technologies, Li-ion batteries have high energy densities, low self-discharge, and no memory effect (although a small memory effect reported in LFP cells has been traced to poorly made cells). Chemistry, performance, cost and safety characteristics vary across types of lithium-ion batteries. Most commercial Li-ion cells use intercalation compounds as the active materials. The anode or negative electrode is usually graphite, although silicon-carbon is also being increasingly used. Cells can be manufactured to prioritize either energy or power density. Handheld electronics mostly use lithium polymer batterie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Van Hove Singularity
A Van Hove singularity is a singularity (non-smooth point) in the density of states (DOS) of a crystalline solid. The wavevectors at which Van Hove singularities occur are often referred to as critical points of the Brillouin zone. For three-dimensional crystals, they take the form of kinks (where the density of states is not differentiable). The most common application of the Van Hove singularity concept comes in the analysis of optical absorption spectra. The occurrence of such singularities was first analyzed by the Belgian physicist Léon Van Hove in 1953 for the case of phonon densities of states. Theory Consider a one-dimensional lattice of ''N'' particle sites, with each particle site separated by distance ''a'', for a total length of ''L'' = ''Na''. Instead of assuming that the waves in this one-dimensional box are standing waves, it is more convenient to adopt periodic boundary conditions: :k=\frac=n\frac where \lambda is wavelength, and ''n'' is an integer. (Positive ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tunnel Field-effect Transistor
The tunnel field-effect transistor (TFET) is an experimental type of transistor. Even though its structure is very similar to a metal-oxide-semiconductor field-effect transistor ( MOSFET), the fundamental switching mechanism differs, making this device a promising candidate for low power electronics. TFETs switch by modulating quantum tunneling through a barrier instead of modulating thermionic emission over a barrier as in traditional MOSFETs. Because of this, TFETs are not limited by the thermal Maxwell–Boltzmann tail of carriers, which limits MOSFET drain current subthreshold swing to about 60 mV/decade of current at room temperature. TFET studies can be traced back to Stuetzer who in 1952 published first investigations of a transistor containing the basic elements of the TFET, a gated p-n junction. The reported surface conductivity control was, however, not related to tunneling. The first TFET was reported in 1965. Joerg Appenzeller and his colleagues at IBM were the first ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Field-effect Transistor
The field-effect transistor (FET) is a type of transistor that uses an electric field to control the flow of current in a semiconductor. FETs ( JFETs or MOSFETs) are devices with three terminals: ''source'', ''gate'', and ''drain''. FETs control the flow of current by the application of a voltage to the gate, which in turn alters the conductivity between the drain and source. FETs are also known as unipolar transistors since they involve single-carrier-type operation. That is, FETs use either electrons (n-channel) or holes (p-channel) as charge carriers in their operation, but not both. Many different types of field effect transistors exist. Field effect transistors generally display very high input impedance at low frequencies. The most widely used field-effect transistor is the MOSFET (metal-oxide-semiconductor field-effect transistor). History The concept of a field-effect transistor (FET) was first patented by Austro-Hungarian physicist Julius Edgar Lilienfeld in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Twistronics
Twistronics (from ''twist'' and ''electronics'') is the study of how the angle (the twist) between layers of two-dimensional materials can change their electrical properties. Materials such as bilayer graphene have been shown to have vastly different electronic behavior, ranging from non-conductive to superconductive, that depends sensitively on the angle between the layers. The term was first introduced by the research group of Efthimios Kaxiras at Harvard University in their theoretical treatment of graphene superlattices. History In 2007, National University of Singapore physicist Antonio Castro Neto hypothesized that pressing two misaligned graphene sheets together might yield new electrical properties, and separately proposed that graphene might offer a route to superconductivity, but he did not combine the two ideas. In 2010 researchers from Universidad Técnica Federico Santa María in Chile found that for a certain angle close to 1 degree the band of the electronic st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The Next Big Future
''The'' () is a grammatical article in English, denoting persons or things already mentioned, under discussion, implied or otherwise presumed familiar to listeners, readers, or speakers. It is the definite article in English. ''The'' is the most frequently used word in the English language; studies and analyses of texts have found it to account for seven percent of all printed English-language words. It is derived from gendered articles in Old English which combined in Middle English and now has a single form used with pronouns of any gender. The word can be used with both singular and plural nouns, and with a noun that starts with any letter. This is different from many other languages, which have different forms of the definite article for different genders or numbers. Pronunciation In most dialects, "the" is pronounced as (with the voiced dental fricative followed by a schwa) when followed by a consonant sound, and as (homophone of pronoun ''thee'') when followed by a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rafi Bistritzer
Rafi Bistritzer (born 1974 in Israel) is an Israeli physicist, and manager of an algorithms group at Applied Materials. He is the winner of the 2020 Wolf Prize in Physics, together with Pablo Jarillo-Herrero and Alan MacDonald, for “pioneering theoretical and experimental work on twisted bilayer graphene.” Biography Bistritzer received a bachelor's degree in physics from Tel Aviv University in 2000. He received an MSc in physics in 2003, and a PhD in physics in 2007, both from the Weizmann Institute of Science. He moved to the United States for a postdoctoral fellowship at the University of Texas at Austin, under the supervision of Prof. Alan MacDonald, where he studied the theoretical physics of bilayer graphene, and specifically twisted bilayer graphene. Their calculations predicted that two parallel graphene sheets twisted at an angle of 1.1 degrees relative to each other (an angle known as the "magic angle") would host flat moiré bands and thus possibly correlated states ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allan H
Allan may refer to: People * Allan (name), a given name and surname, including list of people and characters with this name * Allan (footballer, born 1984) (Allan Barreto da Silva), Brazilian football striker * Allan (footballer, born 1989) (Allan dos Santos Natividade), Brazilian football forward * Allan (footballer, born 1991) (Allan Marques Loureiro), Brazilian football midfielder * Allan (footballer, born 1994) (Allan Christian de Almeida), Brazilian football midfielder * Allan (footballer, born 1997) (Allan Rodrigues de Souza), Brazilian football midfielder Places * Allan, Queensland, Australia * Allan, Saskatchewan, Canada * Allan, the Allaine river's lower course, in France * Allan, Drôme, town in France * Allan, Iran (other), places in Iran Other uses * Allan, a Clan Grant split (or sept) * Ahlawat or Allan, an ethnic clan in India * ''Allan'', a 1966 film directed by Donald Shebib * "Allan" (song), a 1988 song recorded by the French artist Mylène Farmer ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yuan Cao
Yuan Cao () is a Chinese physicist. His research is focused on the properties of two-dimensional materials. He discovered that a stack of two sheets of graphene, cooled to 1.7 kelvins, K, could act as a superconductor or as an insulator when exposed to an electric field. In 2018, ''Nature'' chose him as one of 10 people who mattered that year in science, calling him a "graphene wrangler". Cao was born in Chengdu in 1996, and he attended Shenzhen Yaohua Experimental School starting in 2007. In 2010 he got into the Special Class for the Gifted Young at the University of Science and Technology of China. In 2014 he started graduate school at Massachusetts Institute of Technology, and he obtained his doctorate in 2020. He did research in Pablo Jarillo-Herrero's group studying graphene. After graduating, he has conducted postdoctoral research at MIT. See also * Bilayer graphene Bilayer graphene is a material consisting of two layers of graphene. One of the first reports of bilaye ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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