Optical selection of a multiple phase order in the charge density wave condensateo-TaS3using a spectrally resolved nonequilibrium measurement

Abstract

We investigate the spectrally resolved transient reflectivity changes ⌬R͑T , , ͒ in the charge density wave ͑CDW͒ conductor o-TaS 3 . A distinct near-infrared resonance in this compound emphasizes the characteristic ⌬R͑͒ resonances, and allows a selection of coexisting CDW phases with different nonequilibrium carrier dynamics. Furthermore, the spectrally resolved ⌬R͑͒ characterizes the collective oscillations associated with the individual states. We believe that this demonstration paves the way for the optical selection of the multiphase order that plays an important role in various macroscopic quantum systems.

Nonlocal transport in the charge density waves ofo-TaS3

“…Hence, the source of the nonlocal voltage must be present whether or not the CDW slides. in o-TaS 3 [16], and a subsequent ultrafast optical pump-probe study of o-TaS 3 also provides evidence for two types of CDW phases [17]. Discommensuration, or a lattice of topological dislocations [18] exists from the Peierls temperature to around 50 K [16].…”

“…Moreover, our observation of nonlocal voltages in both the pinned and sliding states reveals the existence of a carrier with long-range correlation, in addition to sliding CDWs and thermally-excited quasiparticles. Finally, we compared our observation to the coexistence of two CDWs in o-TaS 3 [16,17], and found it is closely related to topological dislocations in CDWs.…”

“…The phase diagram of o-TaS 3 [16] shows that there is commensurate CDW at 130 K. Hence, if the life time of the excited soliton is long enough to travel over the 200 µm, it can be a candidate to the origin of the nonlocal voltage. Since we lack unambiguous evidence for the relationship to the CDW soliton within our study, we will pursue the nature of this nonlocal voltage in further studies, including the use of optical [17], acoustic [22] and diffraction [12,16] methods.…”

Carrier dynamics in an organic magnetic superconductor and related salts κ, λ-(BETS)2MCl4(M = Fe, Ga)

“…All the temperatures indicated in this paper are corrected for heating effects by laser irradiation, which were estimated by varying the laser power. The details of our experimental and analysis of the time-resolved spectroscopy are described in previous papers [13][14][15]. By the optical measurement described herein, one obtains the difference in reflectivity (R) from that of equilibrium state as a function of time; ∆R(t).…”

Unifying explanation for carrier relaxation anomaly in gapped systems

“…Usually anomalous T -dependence of τ exp is observed in many gapped systems, for example, phase-ordered systems showing an energy gap opening in the electron band below the transition temperature T c . It has been found that a wide variety of superconductors [1][2][3][4][5][6][7][8][9][10][11][12] and density-wave compounds [13][14][15][16][17][18][19] show diverging behavior of τ exp near T c , as confirmed by femtosecond time-resolved optical spectroscopy [1,4,5,[7][8][9][10][11][12][13][14][15][16][17]19]. The divergence of τ exp in these gapped systems is believed to result from recursive energy transfer between electrons and phonons.…”