Non-Fermi-liquid magic angle effects in high magnetic fields

Abstract

We investigate a theoretical problem of electron-electron interactions in an inclined magnetic field in a quasi-one-dimensional (Q1D) conductor. We show that they result in strong non-Fermi-liquid corrections to a specific heat, provided that the direction of the magnetic field is far from the so-called Lebed's magic angles (LMAs). If magnetic field is directed close to one of the LMAs, the specific heat corrections become small and the Fermi-liquid picture restores. As a result, we predict Fermi-liquid-non-Fermi-liquid angular crossovers in the vicinities of the LMA directions of the field. We suggest to perform the corresponding experiment in the Q1D conductor (Per) 2 Au(mnt) 2 under pressure in magnetic fields of the order of H 25 T. DOI: 10.1103/PhysRevB.94.035162 It is well known that closed electron orbits in a magnetic field in metals are characterized by de Haas-van Alphen and Shubnikov-de Haas quantum oscillations [1]. For open orbits, Landau quantization is not possible and another quantum effect-Bragg reflection from boundaries of the Brillouin zone-plays an important role [2][3][4]. In particular, it has been shown [5][6][7][8] that the latter effect results in the appearance of angular magnetic oscillations, such as the so-called Lebed's magic angles (LMAs), Danner-Kang-Chaikin's (DKC) oscillations, and Lee-Naughton-Lebed's (LNL) ones. It is important that the DKC and LNL oscillations are well explained within the Fermi-liquid approach to open quasi-one-dimensional (Q1D) pieces of the Fermi surface in the Q1D conductors (TMTSF) 2 X (X = ClO 4 , PF 6 , etc.), (DMET) 2 I 3 , and some others [4,[6][7][8]. On the other hand, in many cases, the LMA phenomena are experimentally claimed [9-13] to be of a nonFermi-liquid nature. This was claimed by Chaikin's group for the Nernst effect in (TMTSF) 2 PF 6 [9,10,12], by Brooks' group for the Nernst effect in (TMTSF) 2 ClO 4 [11], and recently by Uji's group [13] for the Hall effect in (TMTSF) 2 ClO 4 . In our opinion, some non-Fermi-liquid effects were also observed in the LMA resistive experiments in the Q1D compound (Per) 2 Au(mnt) 2 by Graf et al. [14].A non-Fermi-liquid theory of the LMA phenomenon was suggested in Ref. [15]. In particular, we showed [15] that an inverse electron-electron scattering time increased at the LMA directions of a magnetic field due to some commensurability effects in a "one-dimensionalized" electron spectrum in a Q1D conductor, resulting from Bragg reflections. Yakovenko studied the same "commensurability" effects in several thermodynamic properties of a Q1D conductor [16], including specific heat (see also Refs. [17,18]). Note that the physical conclusion of the work [16] was similar to that of Ref. [15], that a Q1D metal became more 1D at the LMA directions of the field. There are two main goals of the current article. The first one is that we consider the case of high magnetic fields and come to the conclusion that, at directions of the magnetic field far from one of the LMAs, the corrections to specific heat from electron...

Quantum limit in a quasi-one-dimensional conductor in a high tilted magnetic field

“…[26], where the so-called quasiclassical Peierls substitution method was used. Our conclusion is that the Peierls substitution methods is adequate not only for quasi-classical dimensional crossovers [4][5][6][7][8][9][10][11][12][13][14], where the "sizes" of electron orbits are larger than inter-chain and inter-plane distances, but also for quantum dimensional crossovers [21][22][23][24][25][26][27], where the "sizes' of the orbits are less than inter-chain and inter-plane distances, In some sense, in this paper we have validated previously obtained well-known results [4][5][6][7][8][9][10][11][12][13][14], [21][22][23][24][25][26][27], and some others.…”

“…It was shown [21] that, at high magnetic fields, the typical "sizes" of electron trajectories can become less than inter-layered distances in layered Q1D conductors, which results in the appearance of such unusual phenomenon as the Reentrant Superconductivity [21][22][23]. Different types of quantum 3D → 2D and 3D → 1D dimensional crossovers have been recently studied theoretically [24][25][26][27]. In particular, in Ref.…”

“…We pay attention that all previous considerations of the quantum dimensional crossovers [21][22][23][24][25][26][27] are based on quasi-classical version of the so-called Peierls substitution method [4,1]. The goal of our paper is to solve a fully quantum mechanical problem for a Q1D geometry of electron spectrum in a perpendicular magnetic field.…”