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The presence of attractive interaction between fermions can lead to pairing and superfluidity in an optical lattice. The temperature needed to observe superfluidity is about a tenth of the tunneling energy in the optical lattice, and…

Quantum Gases · Physics 2011-04-27 Viveka Nand Singh , Sanjoy Datta , Pinaki Majumdar

We act on the suggestion that an excitonic insulator state might separate---at very low temperatures---a semimetal from a semiconductor and ask for the nature of these transitions. Based on the analysis of electron-hole pairing in the…

Strongly Correlated Electrons · Physics 2015-06-03 B. Zenker , D. Ihle , F. X. Bronold , H. Fehske

Superconductivity is studied for a fermionic system with attractive four-body interaction. Applying a Green function approach, the gap equation is derived. From the solution, the transition temperature is calculated. Under the condition…

Superconductivity · Physics 2008-02-12 P. Kleinert

We study the electron-hole pair (or excitonic) condensation in the extended Falicov-Kimball model at finite temperatures based on the cluster mean-field-theory approach, where we make the grand canonical exact-diagonalization analysis of…

Strongly Correlated Electrons · Physics 2020-04-22 Masahiro Kadosawa , Satoshi Nishimoto , Koudai Sugimoto , Yukinori Ohta

Exciton bound states in solids between electrons and holes are predicted to form a superfluid at high temperatures. We show that by employing atomically thin crystals such as a pair of adjacent bilayer graphene sheets, equilibrium…

Superconductivity · Physics 2013-05-09 Andrea Perali , David Neilson , Alex R. Hamilton

Graphene thermionic electron emission across high-interface-barrier involves energetic electrons residing far away from the Dirac point where the Dirac cone approximation of the band structure breaks down. Here we construct a full-band…

Mesoscale and Nanoscale Physics · Physics 2019-07-31 Yee Sin Ang , Yueyi Chen , Chuan Tan , L. K. Ang

We investigate a two-component Fermi gas with unequal spin populations along the BCS-BEC crossover. By using the extended BCS equations and the concept of off-diagonal-long-range-order we derive a formula for the condensate number of Cooper…

Quantum Gases · Physics 2014-09-30 G. Bighin , L. Salasnich , G. Mazzarella , L. Dell'Anna

We study theoretically the effect of the fermion and boson densities on the superconductivity transition critical temperature $(T_c)$ of a two dimensional electron gas (2DEG), where superconductivity is mediated by a Bose-Einstein…

Superconductivity · Physics 2014-10-15 E. D. Cherotchenko , T. Espinosa-Ortega , A. V. Nalitov , I. A. Shelykh , A. V. Kavokin

We analyze a possible superconductivity in the hole-doped system of layered hydrogenized graphene by taking into account thermal fluctuations of the order parameter. In particular, we demonstrate that in the one-layer case the values of the…

Superconductivity · Physics 2015-05-27 V. M. Loktev , V. Turkowski

Using the projector-based renormalization method we investigate the formation of the excitonic insulator phase in the two-dimensional (2D) spinless Falicov-Kimball model with dispersive $f$ electrons and address the existence of excitonic…

Strongly Correlated Electrons · Physics 2015-05-27 Van-Nham Phan , Holger Fehske , Klaus W. Becker

Currently, superconductivity in two-dimensional (2D) materials is a hot topic of research owing to their potential technological applications. Here, we report observation of superconductivity in a 2D Nb2C MXene with transition temperature…

Monolayer C$_3$N is an emerging two-dimensional indirect band gap semiconductor with interesting mechanical, thermal, and electronic properties. In this work we present a description of C$_3$N electronic and dielectric properties, focusing…

Mesoscale and Nanoscale Physics · Physics 2022-04-26 Miki Bonacci , Matteo Zanfrognini , Elisa Molinari , Alice Ruini , Marilia J. Caldas , Andrea Ferretti , Daniele Varsano

This article reviews the status of current research on the 112-phase of pnictides. The 112-phase has gained augmented attention due to the recent discovery of high-temperature superconductivity in $\cl$ with a maximum critical temperature…

Superconductivity · Physics 2017-04-05 S. J. Ray , L. Alff

We study a gas of fermions undergoing a wide resonance s-wave BCS-BEC crossover, in the BEC regime at zero temperature. We calculate the chemical potential and the speed of sound of this Bose-condensed gas, as well as the condensate…

Superconductivity · Physics 2009-11-11 J. Levinsen , V. Gurarie

Understanding the origins of unconventional superconductivity has been a major focus of condensed matter physics for many decades. While many questions remain unanswered, experiments have found that the systems with the highest critical…

Quantum Gases · Physics 2021-06-23 Lennart Sobirey , Hauke Biss , Niclas Luick , Markus Bohlen , Henning Moritz , Thomas Lompe

We calculate theoretically the optical conductivity in the bilayer graphene by considering Kubo-Green-Matsubara formalism. Different regimes of the interlayer coupling parameter have been considered in the paper. We show that the excitonic…

Strongly Correlated Electrons · Physics 2019-01-30 V. Apinyan , T. K. Kopeć

We observe many-body pairing in a two-dimensional gas of ultracold fermionic atoms at temperatures far above the critical temperature for superfluidity. For this, we use spatially resolved radio-frequency spectroscopy to measure pairing…

The two-dimensional, colossal magnetoresistive system GdI_2 develops an unusual metallic state below its ferromagnetic transition and becomes insulating at low temperatures. It is argued that this geometrically frustrated, correlated poor…

Strongly Correlated Electrons · Physics 2009-11-13 A. Taraphder , M. S. Laad , L. Craco , A. N. Yaresko

The heating of carriers in an intrinsic graphene under an abrupt switching off a dc electric field is examined taking into account both the energy relaxation via acoustic and optic phonons and the interband generation-recombination…

Mesoscale and Nanoscale Physics · Physics 2015-05-20 P. N. Romanets , F. T. Vasko

Plasmonic excitations behave fundamentally different in layered materials in comparison to bulk systems. They form gapless modes, which in turn couple at low energies to the electrons. Thereby they can strongly influence superconducting…

Superconductivity · Physics 2018-03-14 M. Rösner , R. E. Groenewald , G. Schönhoff , J. Berges , S. Haas , T. O. Wehling