Physica B 281&282 (2000) 784}785 First-principles study of the angle-dependent magnetoresistance oscillation in Sr  RuO  Fumiyuki Ishii*, Tamio Oguchi Department of Physical Sciences, Hiroshima University, 1-3-1 Kagamiyama, Higashi-hiroshima, 739-8526, Japan Abstract We performed Shockley tube-integral in Sr  RuO  with the Fermi velocity and cyclotron mass obtained from "rst-principles band structure calculations to analyse angle-dependent magnetoresistance oscillation (AMRO). The calculated results are in good agreement with experiment data. The overall peak structure of AMRO as a function of  can be explained by the  branch of Fermi surface.  2000 Elsevier Science B.V. All rights reserved. Keywords: Sr  RuO  ; AMRO; Fermi surface The layered perovskite Sr  RuO  has attracted much attention because of its similarities to the high-¹  cuprates. Though the mechanism of superconductivity in Sr  RuO  has not yet been understood, there are several models to explain it related to Fermi surface (FS) topology [1]. FS of Sr  RuO  has been revealed by electronic band structure calculations within local density approxima- tion (LDA) [2,3] and measurements of quantum oscilla- tion by Shubnikov}de Haas (SdH) and de Haas}van Alphen (dHvA) e!ects [4] and angle-resolved photoemis- sion (ARPES) [5}7]. However, the topology of FS in Sr  RuO  is still controversial because there are discrep- ancies between ARPES and LDA calculations. Recently, angle-dependent magnetoresistance oscilla- tion (AMRO) in Sr  RuO  has been observed [8], pro- viding new information about the FS topology which could not be obtained by dHvA and SdH. AMRO are often observed in quasi-2D systems such as organic con- ductors. Analysis of AMRO has been performed based on a simple tight-binding model [9,10], with which the energy bands contributing to FS can be expressed well in organic conductors. However, the energy bands are not so simple in Sr  RuO  and should be represented based on "rst-principles band structure calculations. * Corresponding author. Fax: #81-824-24-7395. E-mail address: fumiyuki@ipc.hiroshima-u.ac.jp (F. Ishii) From the previous band structure calculations, there exist three sheets of FS in Sr  RuO  , one hole branch  around X point and two electron branches  and  around  point. The  branch is made with the band composed of Ru d  orbitals in the Ru}O  plane and forms a nearly quasi-2D cylindrical FS. On the other hand, the  and  branches are reconnected quasi-1D FSs made with bands composed of d  and d  orbitals. From analysis of AMRO based on a simple model FS in Sr  RuO  [8], the observed peaks may be understood by using both the  and  branches. In this study, we calculate conductivity tensor   using the Boltzmann equation   " 1 4 e   dk  mH      d    d v  (, k  )v  (!, k  ) e   1!e   , (1) where v  denotes the i component of the Fermi velocity,  the phase of orbit, mH the cyclotron mass, k  the wave vector parallel to the magnetic "eld,   the cyclotron frequency and  the relaxation time. This formula is called Shockley tube-integral [10,11], performed along electron orbits which is perpendicular to the magnetic "eld. The cyclotron mass mH depends on each orbit. We perform this integral with the Fermi velocity and cyclo- tron mass obtained from "rst-principles band structure 0921-4526/00/$ - see front matter  2000 Elsevier Science B.V. All rights reserved. PII: S 0 9 2 1 - 4 5 2 6 ( 9 9 ) 0 1 2 1 1 - 9