Magnetotransport properties of two-dimensional electron gases （2DEG） in AlxGa1-x N/GaN heterostructures with different Al compositions are investigated by magnetotransport measurements at low temperatures and in hig...Magnetotransport properties of two-dimensional electron gases （2DEG） in AlxGa1-x N/GaN heterostructures with different Al compositions are investigated by magnetotransport measurements at low temperatures and in high magnetic fields. It is found that heterostructures with a lower Al composition in the barrier have lower 2DEG concentration and higher 2DEG mobility.展开更多
Two-dimensional （2D） materials are highly promising for flexible electronics, and graphene is the only well-studied transparent conductor. Herein, density functional theory has been used to explore a new transparent...Two-dimensional （2D） materials are highly promising for flexible electronics, and graphene is the only well-studied transparent conductor. Herein, density functional theory has been used to explore a new transparent conducting material via adsorption of H on a 2D β-GaS sheet. This adsorption results in geometrical changes to the local structures around the H. The calculated electronic structures reveal metallic characteristics of the 2D α-GaS material upon H adsorption and a large optical band gap of 2.72 eV with a significant Burstein-Moss shift of 0.67 eVo The simulated electrical resistivity is as low as 10^-4 Ω.cm, comparable to the benchmark for ITO thin films.展开更多
This paper is devoted to results on the Moser-Trudinger-Onofri inequality, or the Onofri inequality for brevity. In dimension two this inequality plays a role similar to that of the Sobolev inequality in higher dimens...This paper is devoted to results on the Moser-Trudinger-Onofri inequality, or the Onofri inequality for brevity. In dimension two this inequality plays a role similar to that of the Sobolev inequality in higher dimensions. After justifying this statement by recovering the Onofri inequality through various limiting procedures and after reviewing some known results, the authors state several elementary remarks.Various new results are also proved in this paper. A proof of the inequality is given by using mass transportation methods(in the radial case), consistently with similar results for Sobolev inequalities. The authors investigate how duality can be used to improve the Onofri inequality, in connection with the logarithmic Hardy-Littlewood-Sobolev inequality.In the framework of fast diffusion equations, it is established that the inequality is an entropy-entropy production inequality, which provides an integral remainder term. Finally,a proof of the inequality based on rigidity methods is given and a related nonlinear flow is introduced.展开更多
文摘Magnetotransport properties of two-dimensional electron gases （2DEG） in AlxGa1-x N/GaN heterostructures with different Al compositions are investigated by magnetotransport measurements at low temperatures and in high magnetic fields. It is found that heterostructures with a lower Al composition in the barrier have lower 2DEG concentration and higher 2DEG mobility.
基金This work was financially supported by National University of Singapore, Ministry of Education of Singapore, Ministry of Defence of Singapore, National Research Foundation of Singapore and National Natural Science Foundation of China （Nos. 21233006 and 21473164）.
文摘Two-dimensional （2D） materials are highly promising for flexible electronics, and graphene is the only well-studied transparent conductor. Herein, density functional theory has been used to explore a new transparent conducting material via adsorption of H on a 2D β-GaS sheet. This adsorption results in geometrical changes to the local structures around the H. The calculated electronic structures reveal metallic characteristics of the 2D α-GaS material upon H adsorption and a large optical band gap of 2.72 eV with a significant Burstein-Moss shift of 0.67 eVo The simulated electrical resistivity is as low as 10^-4 Ω.cm, comparable to the benchmark for ITO thin films.
基金supported by the Projects STAB and Kibord of the French National Research Agency(ANR)the Project No NAP of the French National Research Agency(ANR)the ECOS Project(No.C11E07)
文摘This paper is devoted to results on the Moser-Trudinger-Onofri inequality, or the Onofri inequality for brevity. In dimension two this inequality plays a role similar to that of the Sobolev inequality in higher dimensions. After justifying this statement by recovering the Onofri inequality through various limiting procedures and after reviewing some known results, the authors state several elementary remarks.Various new results are also proved in this paper. A proof of the inequality is given by using mass transportation methods(in the radial case), consistently with similar results for Sobolev inequalities. The authors investigate how duality can be used to improve the Onofri inequality, in connection with the logarithmic Hardy-Littlewood-Sobolev inequality.In the framework of fast diffusion equations, it is established that the inequality is an entropy-entropy production inequality, which provides an integral remainder term. Finally,a proof of the inequality based on rigidity methods is given and a related nonlinear flow is introduced.
