Band-selective Holstein polaron in Luttinger liquid material A0.3MoO3 (A = K, Rb)

Abstract

Abstract(Quasi-)one-dimensional systems exhibit various fascinating properties such as Luttinger liquid behavior, Peierls transition, novel topological phases, and the accommodation of unique quasiparticles (e.g., spinon, holon, and soliton, etc.). Here we study molybdenum blue bronze A0.3MoO3 (A = K, Rb), a canonical quasi-one-dimensional charge-density-wave material, using laser-based angle-resolved photoemission spectroscopy. Our experiment suggests that the normal phase of A0.3MoO3 is a prototypical Luttinger liquid, from which the charge-density-wave emerges with decreasing temperature. Prominently, we observe strong renormalizations of band dispersions, which are recognized as the spectral function of Holstein polaron derived from band-selective electron-phonon coupling in the system. We argue that the strong electron-phonon coupling plays an important role in electronic properties and the charge-density-wave transition in blue bronzes. Our results not only reconcile the long-standing heavy debates on the electronic properties of blue bronzes but also provide a rare platform to study interesting excitations in Luttinger liquid materials.

Bipolaronic Nature of the Pseudogap in Quasi-One-Dimensional (TaSe4)2I Revealed via Weak Photoexcitation

“…These relatively long response and relaxation times are consistent with photoinduced structural changes, since the lattice needs time to rearrange. , However, in the case of another prototypical quasi-1D material, Rb 0.3 MoO 3 , it exhibits dramatically faster (∼10×) relaxation of the excited in-gap states of only ∼60 fs. The pseudogap in this material was variously attributed to either the presence of a polaron gap or the formation of a Luttinger liquid . Our observation of fast response and relaxation times suggests that the origin of the pseudogap in Rb 0.3 MoO 3 is likely electronic in nature, such as hot carriers losing energy to Luttinger plasmons, thus favoring the recent Luttinger-liquid explanation .…”

“…Multiple mechanisms have been proposed to underly the formation of a pseudogap, such as polaronic interactions, , Luttinger-liquid behavior, , the Efros–Shklovskii effect, , and charge density wave (CDW) fluctuations . The physical origins of such interactions are very different even though they can give rise to similar pseudogaps; strong electron–phonon coupling and charge–lattice distortions support polaronic and CDW orders, while electron–electron interactions support Luttinger-liquid behavior.…”

Development of a laser-based angle-resolved-photoemission spectrometer with sub-micrometer spatial resolution and high-efficiency spin detection

“…Moreover, it can extract subtle information such as electron-electron correlation, electron-phonon interaction, and spin-orbit coupling 2,3 . In the past decades, ARPES has become a powerful tool for the exploration of numerous intriguing quantum phenomena such as high-temperature superconductivity [4][5][6][7] , heavyfermion materials 5,8,9 , charge/spin density waves [10][11][12] , magnetism 13,14 , and topological quantum physics [15][16][17] .…”

Real-time non-adiabatic dynamics in the one-dimensional Holstein model: Trajectory-based vs exact methods

“…6 This coupled dynamics of an electron-bosonic composite system is often initiated by the excitation with an electromagnetic field, and complexity can further increase if the quantum nature of the electromagnetic field and its bosonic excitations are taken into account explicitly. [7][8][9][10][11][12] Bosonic excitations naturally emerge in condensed matter, e.g., plasmons, 13 phonons, [14][15][16] or magnons. 13 Here, such excitations can couple to electrons and influence the electronic properties.…”

“…125,126 The CDW-to-metallic transition has recently been observed in experiments. 16 The physics of polarons and the CDW-tometallic transition described in the Holstein model generally involve a strong coupling between oscillators and electrons, for whose description non-perturbative theoretical methods are necessary even in equilibrium, see Ref. 15 and references therein.…”