1996/05/31 by R. Eder, P. Wrobel, P. Wróbel +1 · 1 citation
Physics and Astronomy · #Advanced Chemical Physics Studies #Antiferromagnetism #Atomic physics #Condensed matter physics #Conductivity #Correlation function (quantum field theory) #Electron #Energy (signal processing) #Excitation #Excited state #Hubbard model #Mathematical physics #Omega #Optical conductivity #Physics #Physics of Superconductivity and Magnetism #Quantum and electron transport phenomena #Quantum mechanics #Quasiparticle #Spin (aerodynamics) #Spinon #String (physics) #Superconductivity #cond-mat #t-J model
paper · pdf · doi:10.1103/physrevb.54.r11034
Minor revisions: typos corrected, some explanations added; Accepted for PRB/Rapid Communications
arxiv created 1996/09/14 · openalex publication_date 1996/10/15 · openalex created_date 2016/06/24 · arxiv updated 2016/08/31 · openalex updated_date 2026/08/05
We present an exact-diagonalization study of the frequency- and wave-vector-dependent conductivity \ensuremathσ(q, \ensuremathω) in small clusters in the two-dimensional t\ensuremath-J model. Unlike the related dynamical density correlation function, \ensuremathσ(q=0, \ensuremathω) in the underdoped regime has the exchange constant J as its characteristic energy scale and is dominated by a resonancelike excitation with frequency \ensuremath∼1.7J. We interpret this as transition to a p-like excited state of a spin-bag-type quasiparticle (or, alternatively, a tightly bound spinon-holon pair) and show that a simple calculation based on the string picture explains the numerical results semiquantitatively. For doping levels >~25%t remains the only energy scale of \ensuremathσ(q=0, \ensuremathω).