skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Transient reflectance of photoexcited Cd{sub 3}As{sub 2}

Abstract

We report ultrafast transient-grating measurements of crystals of the three-dimensional Dirac semimetal cadmium arsenide, Cd{sub 3}As{sub 2}, at both room temperature and 80 K. After photoexcitation with 1.5-eV photons, charge-carriers relax by two processes, one of duration 500 fs and the other of duration 3.1 ps. By measuring the complex phase of the change in reflectance, we determine that the faster signal corresponds to a decrease in absorption, and the slower signal to a decrease in the light's phase velocity, at the probe energy. We attribute these signals to electrons' filling of phase space, first near the photon energy and later at lower energy. We attribute their decay to cooling by rapid emission of optical phonons, then slower emission of acoustic phonons. We also present evidence that both the electrons and the lattice are strongly heated.

Authors:
;  [1]; ;  [2]; ;  [3]
  1. Department of Physics, Santa Clara University, 500 El Camino Real, Santa Clara, California 95053-0315 (United States)
  2. Institute of Applied Physics, Academy of Sciences of Moldova, Academiei str. 5, MD 2028 Chisinau (Moldova, Republic of)
  3. Departments of Electrical Engineering and Computer Science, University of Wisconsin-Milwaukee, P.O. Box 413, Milwaukee, Wisconsin 53201 (United States)
Publication Date:
OSTI Identifier:
22412552
Resource Type:
Journal Article
Resource Relation:
Journal Name: Applied Physics Letters; Journal Volume: 106; Journal Issue: 23; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 36 MATERIALS SCIENCE; CADMIUM ARSENIDES; CHARGE CARRIERS; ELECTRONS; EXCITATION; PHASE SPACE; PHASE VELOCITY; PHONONS; PHOTONS; TEMPERATURE RANGE 0273-0400 K; THREE-DIMENSIONAL LATTICES

Citation Formats

Weber, C. P., E-mail: cweber@scu.edu, Berggren, Bryan S., Arushanov, Ernest, Nateprov, Alex, Hosseini, Tahereh, and Kouklin, Nikolai. Transient reflectance of photoexcited Cd{sub 3}As{sub 2}. United States: N. p., 2015. Web. doi:10.1063/1.4922528.
Weber, C. P., E-mail: cweber@scu.edu, Berggren, Bryan S., Arushanov, Ernest, Nateprov, Alex, Hosseini, Tahereh, & Kouklin, Nikolai. Transient reflectance of photoexcited Cd{sub 3}As{sub 2}. United States. doi:10.1063/1.4922528.
Weber, C. P., E-mail: cweber@scu.edu, Berggren, Bryan S., Arushanov, Ernest, Nateprov, Alex, Hosseini, Tahereh, and Kouklin, Nikolai. Mon . "Transient reflectance of photoexcited Cd{sub 3}As{sub 2}". United States. doi:10.1063/1.4922528.
@article{osti_22412552,
title = {Transient reflectance of photoexcited Cd{sub 3}As{sub 2}},
author = {Weber, C. P., E-mail: cweber@scu.edu and Berggren, Bryan S. and Arushanov, Ernest and Nateprov, Alex and Hosseini, Tahereh and Kouklin, Nikolai},
abstractNote = {We report ultrafast transient-grating measurements of crystals of the three-dimensional Dirac semimetal cadmium arsenide, Cd{sub 3}As{sub 2}, at both room temperature and 80 K. After photoexcitation with 1.5-eV photons, charge-carriers relax by two processes, one of duration 500 fs and the other of duration 3.1 ps. By measuring the complex phase of the change in reflectance, we determine that the faster signal corresponds to a decrease in absorption, and the slower signal to a decrease in the light's phase velocity, at the probe energy. We attribute these signals to electrons' filling of phase space, first near the photon energy and later at lower energy. We attribute their decay to cooling by rapid emission of optical phonons, then slower emission of acoustic phonons. We also present evidence that both the electrons and the lattice are strongly heated.},
doi = {10.1063/1.4922528},
journal = {Applied Physics Letters},
number = 23,
volume = 106,
place = {United States},
year = {Mon Jun 08 00:00:00 EDT 2015},
month = {Mon Jun 08 00:00:00 EDT 2015}
}
  • The electrochemical oxidation of a metallic anode (zinc or cadmium) in an acetonitrile solution of a series of arenephosphinothiol ligands, 2-(Ph{sub 2}P)C{sub 6}H{sub 4}SH, 2-(Ph{sub 2}P)-6-(Me{sub 3}Si)C{sub 6}H{sub 3}SH, 2-(Ph{sub 2}PO)-6-(Me{sub 3}Si)C{sub 6}H{sub 3}SH, and PhP-(C{sub 6}H{sub 4}SH-2){sub 2} [abbreviated RP-(SH){sub x}, x = 1 or 2], affords [M(RP-S){sub 2}] and [M(RP-S{sub 2})], M = Zn, Cd. Adducts of several of these compounds with 1,10-phenanthroline and 2,2{prime}-bipyridine have also been obtained by addition of these coligands to the electrolysis phase. The compounds obtained have been characterized by microanalysis, IR, UV-visible, FAB spectrometry and {sup 1}H, {sup 31}P NMR spectroscopic studies.more » The compounds [Cd{sub 2}{l{underscore}brace}2-(Ph{sub 2}PO)-C{sub 6}H{sub 4}S{r{underscore}brace}{sub 4}]CH{sub 3}CN (1), [Zn{l{underscore}brace}2-(Ph{sub 2}P)-6-(Me{sub 3}Si)C{sub 6}H{sub 3}S{r{underscore}brace}{sub 2}] (2), [Cd{l{underscore}brace}2-(Ph{sub 2}PO)-6-(Me{sub 3}Si)C{sub 6}H{sub 3}S{r{underscore}brace}{sub 2}(CH{sub 3}OH)] (3), and [Zn{l{underscore}brace}PhPO(C{sub 6}H{sub 4}S-2){sub 2}{r{underscore}brace}(bipy)] (4), have been also characterized by single-crystal X-ray diffraction. Compound 1 is binuclear with a {l{underscore}brace}Cd{sub 2}S{sub 2}{r{underscore}brace} core and distorted trigonal bipyramidal {l{underscore}brace}CdO{sub 2}S{sub 3}{r{underscore}brace} geometry about the Cd sites. Compounds 2, 3, and 4 are mononuclear with distorted tetrahedral {l{underscore}brace}ZnP{sub 2}S{sub 2}{r{underscore}brace}, distorted square pyramidal {l{underscore}brace}CdO{sub 3}S{sub 2}{r{underscore}brace}, and distorted trigonal bipyramidal {l{underscore}brace}ZnON{sub 2}S{sub 2}{r{underscore}brace} geometries, respectively.« less
  • All possible mixed-ligand complexes of the formula LL`Cd L,L` = [HB(pz){sub 3}]{sup -}, [HB(3,5-Me{sub 2}pz){sub 3}]{sup -}, [B(pz){sub 4}]{sup -}, [HB(3-Phpz){sub 3}]{sup -} (pz = pyrazolyl) were prepared by the reaction of a 1/1/1 molar ratio of the desired ligand salts and CdCl{sub 2}. The new symmetrical complex [(3-Phpz){sub 3}]{sub 2}Cd was prepared from 2 equiv of the ligand salt and CdCl{sub 2}. The solid state structures of [HB(pz){sub 3}]{sub 2}Cd (1), [HB(3-Phpz){sub 3}]{sub 2}Cd (4), and [B(pz){sub 4}]Cd[HB(3-Phpz){sub 3}] (10) have been characterized by X-ray crystallography. All three are pseudo-octahedral, but the structures of both 4 and 10 aremore » distorted by a rotational movement of one gland relative to the other gland. The solution {sup 113}Cd NMR chemical shifts for complexes containing the [HB(3-Phpz){sub 3}]{sup -} are substantially more shielded than the other complexes in the series. A regression analysis of the solution {sup 113}Cd NMR chemical shifts for all these complexes for the shift caused by each ligand relative to Cd(ClO{sub 4}){sub 2} shows a good correlation of the calculated and observed chemical shifts of these complexes. 28 refs., 9 figs., 5 tabs.« less
  • The reaction of CdCl{sub 2} with equimolar amounts of K[HB(3,5-Me{sub 2}pz){sub 3}] (pz = pyrazolyl) and K[H{sub 2}B(3,5-Me{sub 2}pz){sub 2}] or K[HB(3-Phpz){sub 3}] and either K[H{sub 2}B(pz){sub 2}] or K[H{sub 2}B(3,5-Me{sub 2}pz){sub 2}] yields, respectively, the five-coordinate complexes [HB(3,5-Me{sub 2}pz){sub 3}]Cd[H{sub 2}B(3,5-Me{sub 2}pz){sub 2}] (1), [HB(3-Phpz){sub 3}]Cd[H{sub 2}B(pz){sub 2}] (2) and [HB(3-Phpz){sub 3}]Cd[H{sub 2}B(3,5-Me{sub 2}pz){sub 2}] (3). The structure of 3 has been characterized in the solid state by X-ray crystallography. The complex has a square pyramidal arrangement of the nitrogen donor atoms about cadmium. Solution state {sup 1}H NMR studies indicate that this geometry is retained in solution. Complexesmore » 1-3 show solution {sup 113}Cd NMR resonances in the range {delta} 193.6-224.3 ppm (vs Cd(Cl0{sub 4}){sub 2}). The complexes containing the [HB(3-Phpz){sub 3}]{sup -} ligand have the more shielded resonances. This range overlaps the region observed for poly(pyrazolyl)borate complexes with CdN{sub 6} inner cores ({delta} 94.0-221.1 ppm). Six complexes with a CdN{sub 3}O{sub 2} inner core of the formula [HB(3-Phpz){sub 3}]Cd[(RCO){sub 2}CH] (R = Bu{sup t}, Ph, CF{sub 3}), [HB(3-Bu{sup t}pz){sub 3}]Cd[(Bu{sup t}CO){sub 2}CH], [B(3-Pr{sup i}pz){sub 4}]Cd(Bu{sup t}CO){sub 2}CH], and [HB(3-Bu{sup t}pz){sub 3}Cd(CH{sub 3}CO{sub 2}) have been prepared by the reaction of CdCl{sub 2} or Cd(NO{sub 3}){sub 2} and the appropriate ligand salts. Two complexes with N{sub 3}S{sub 2} inner cores, [HB(3,5-Me{sub 2}pz){sub 3}]Cd[Et{sub 2}NCS{sub 2}] (10) and [HB(3-Phpz){sub 3}]Cd[Et{sub 2}NCS{sub 2}] (11), have been prepared. The structure of 10 has been determined by X-ray crystallography. The donor atoms are arranged about cadmium in an irregular five-coordinate geometry.« less
  • Both CD{sub 2}OH and CD{sub 3}O were prepared {ital in} {ital situ} by the reaction of F atoms with CD{sub 3}OH, and studied by photoionization mass spectrometry. The adiabatic ionization potential (I.P.) of CD{sub 2}OH was found to be 7.540{plus minus}0.006 eV, in good agreement with the photoelectron spectroscopy (PES) value, 7.55{plus minus}0.01 eV. However, the adiabatic I.P. of CD{sub 3}O was determined to be 10.726{plus minus}0.008 eV, in marked contrast to the PES value for CH{sub 3}O, 7.37{plus minus}0.03 eV, but in the expected range based on reported values of {Delta}{ital H}{sup 0}{sub {ital f}}(CH{sub 3}O{sup +}) and {Delta}{italmore » H}{sup 0}{sub {ital f}}(CH{sub 3}O). From selected values of {Delta}{ital H}{sup 0}{sub {ital f}0}(CH{sub 2}OH{sup +}) {le}172.0{plus minus}0.7 kcal/mol and {Delta}{ital H}{sup 0}{sub {ital f}0}(CH{sub 3}O) =5.9{plus minus}1.0 kcal/mol, we deduce {Delta}{ital H}{sup 0}{sub {ital f}0}(CH{sub 2}OH) {le}{minus}2.1{plus minus}0.7 kcal/mol and {Delta}{ital H}{sup 0}{sub {ital f}0}(CH{sub 3}O{sup +}) =253.1{plus minus}1.0 kcal/mol.« less