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Haratani K, Hayashi H, Tanaka T, Kaneda H, Togashi Y, Sakai K, Hayashi K, Tomida S, Chiba Y, Yonesaka K, Nonagase Y, Takahama T, Tanizaki J, Tanaka K, Yoshida T, Tanimura K, Takeda M, Yoshioka H, Ishida T, Mitsudomi T, Nishio K, Nakagawa K. Tumor immune microenvironment and nivolumab efficacy in EGFR mutation-positive non-small-cell lung cancer based on T790M status after disease progression during EGFR-TKI treatment. Ann Oncol 2018; 28:1532-1539. [PMID: 28407039 DOI: 10.1093/annonc/mdx183] [Citation(s) in RCA: 239] [Impact Index Per Article: 34.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2017] [Indexed: 12/22/2022] Open
Abstract
Background The efficacy of programmed death-1 blockade in epidermal growth factor receptor gene (EGFR) mutation-positive non-small-cell lung cancer (NSCLC) patients with different mechanisms of acquired resistance to EGFR tyrosine kinase inhibitors (TKIs) is unknown. We retrospectively evaluated nivolumab efficacy and immune-related factors in such patients according to their status for the T790M resistance mutation of EGFR. Patients and methods We identified 25 patients with EGFR mutation-positive NSCLC who were treated with nivolumab after disease progression during EGFR-TKI treatment (cohort A). Programmed death-ligand 1 (PD-L1) expression and tumor-infiltrating lymphocyte (TIL) density in tumor specimens obtained after acquisition of EGFR-TKI resistance were determined by immunohistochemistry. Whole-exome sequencing of tumor DNA was carried out to identify gene alterations. The relation of T790M status to PD-L1 expression or TIL density was also examined in an independent cohort of 60 patients (cohort B). Results In cohort A, median progression-free survival (PFS) was 2.1 and 1.3 months for T790M-negative and T790M-positive patients, respectively (P = 0.099; hazard ratio of 0.48 with a 95% confidence interval of 0.20-1.24). Median PFS was 2.1 and 1.3 months for patients with a PD-L1 expression level of ≥1% or <1%, respectively (P = 0.084; hazard ratio of 0.37, 95% confidence interval of 0.10-1.21). PFS tended to increase as the PD-L1 expression level increased with cutoff values of ≥10% and ≥50%. The proportion of tumors with a PD-L1 level of ≥10% or ≥50% was higher among T790M-negative patients than among T790M-positive patients of both cohorts A and B. Nivolumab responders had a significantly higher CD8+ TIL density and nonsynonymous mutation burden. Conclusion T790M-negative patients with EGFR mutation-positive NSCLC are more likely to benefit from nivolumab after EGFR-TKI treatment, possibly as a result of a higher PD-L1 expression level, than are T790M-positive patients.
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Journal Article |
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Ohtsuka Y, Munakata M, Tanimura K, Ukita H, Kusaka H, Masaki Y, Doi I, Ohe M, Amishima M, Homma Y. Smoking promotes insidious and chronic farmer's lung disease, and deteriorates the clinical outcome. Intern Med 1995; 34:966-71. [PMID: 8563097 DOI: 10.2169/internalmedicine.34.966] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Although the prevalence of serum precipitating antibodies for farmer's lung disease (FLD) is lower in smokers than in nonsmokers and FLD predominates in nonsmokers, the affects of smoking on the clinical course of the disease is not known. We compared the clinical findings and the prognosis between 12 smokers (SM-FLD) and 31 non-smokers with FLD (NS-FLD). There was no difference in age, sex, working years on farm, clinical symptoms, laboratory findings, radiographic findings, between the two groups. However, for the type of onset on the first visit for FLD, "acute single episode" type was less common, and "recurrent" and "insidious onset" types were more common in SM-FLD than in NS-FLD (8.3 vs 58.1, 91.7 vs 41.9%, respectively, p < 0.05). Although working status and mask wearing status were not significantly different between the two groups after the diagnosis of FLD, patients with symptoms and/or radiographic abnormalities of FLD of more than 6 months were found more frequently in SM-FLD than in NS-FLD (66.7 vs 19.4%, p < 0.005). And also SM-FLD had more recurrences of FLD than NS-FLD after the initial diagnosis of FLD (1.58 +/- 1.56 vs 0.47 +/- 1.07, p < 0.05). SM-FLD tended to have lower % VC than NS-FLD (73.6 +/- 7.4 vs 88.5 +/- 3.9%, respectively, p = 0.06). Regarding the prognosis, the 10-year survival rates were 70.7% in SM-FLD, and 91.5% in NS-FLD (p < 0.05). These results suggest that smoking may make FLD insidious and chronic, and deteriorates the clinical outcome.
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Tanimura K, Itoh C, Itoh N. Transient optical absorption and luminescence induced by band-to-band excitation in amorphous SiO2. ACTA ACUST UNITED AC 2000. [DOI: 10.1088/0022-3719/21/9/026] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Yoshizaki S, Tanimura K, Tamada S, Yabuuchi Y, Nakagawa K. Sympathomimetic amines having a carbostyril nucleus. J Med Chem 1976; 19:1138-42. [PMID: 10441 DOI: 10.1021/jm00231a011] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
A series of new sympathomimetic amines containing an 8-hydroxycarbostyril moiety was synthesized. These compounds probably exist as resonance hybrids having two acidic hydrogen atoms in locations approximating to those of the hydroxyl groups of catechol-containing adrenergic agents. In an in vitro test, many of these compounds showed potent activity for relaxation of guinea pig tracheal smooth muscle. One of the compounds was 24 000 times more potent than isoproterenol. Their actions on cardiac muscle were also examined in vitro by measuring increase in the beating rate of the right atria of guinea pigs. Several of the compounds appeared to be beta-selective. Some of the compounds seem suitable for use as bronchodilators. The structure-activity relationships of these compounds were discussed in comparison with those of catecholamines.
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Comparative Study |
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Itoh C, Tanimura K, Itoh N, Itoh M. Threshold energy for photogeneration of self-trapped excitons in SiO2. PHYSICAL REVIEW. B, CONDENSED MATTER 1989; 39:11183-11186. [PMID: 9947942 DOI: 10.1103/physrevb.39.11183] [Citation(s) in RCA: 59] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Homma Y, Ohtsuka Y, Tanimura K, Kusaka H, Munakata M, Kawakami Y, Ogasawara H. Can interstitial pneumonia as the sole presentation of collagen vascular diseases be differentiated from idiopathic interstitial pneumonia? Respiration 1995; 62:248-51. [PMID: 8560090 DOI: 10.1159/000196457] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
We prospectively followed 68 patients diagnosed as idiopathic interstitial pneumonia (IIP) over a period of 1-11 years. Thirteen patients (19%) subsequently developed systemic manifestations of collagen vascular diseases (CVD) and were diagnosed as having had interstitial pneumonia as the sole presentation of CVD (CVD-IP). Compared with the 55 IIP patients, the 13 CVD-IP patients were relatively younger, predominantly female, and had a lower incidence of dust inhalation in their history. They also had a higher erythrocyte sedimentation rate, higher incidence of the x-ray finding of discoid atelectasis in the lower lung fields, and a better prognosis than the IIP patients. However, these features did not clearly distinguish the two groups. We conclude that the patients clinically and/or histologically defined as suffering from IIP cannot be distinguished from CVD-IP patients before systemic signs of CVD appear in the latter group.
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Comparative Study |
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Kanasaki J, Inami E, Tanimura K, Ohnishi H, Nasu K. Formation of sp3-bonded carbon nanostructures by femtosecond laser excitation of graphite. PHYSICAL REVIEW LETTERS 2009; 102:087402. [PMID: 19257783 DOI: 10.1103/physrevlett.102.087402] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2008] [Indexed: 05/13/2023]
Abstract
A scanning tunneling microscopy study and ab initio total energy calculations have identified the atomic-level structure of novel sp;{3}-bonded carbon nanoscale domains formed dynamically from graphite by femtosecond-laser excitation. The structure is characterized by a pseudo sp;{3}-bonding configuration that results in inward displacement of surface carbon atoms by 0.5 A in every third row along the [11[over ]00] orientation. This structural periodicity is unique and differs from conventional phases of diamond.
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Puchin VE, Shluger AL, Tanimura K, Itoh N. Model of self-trapped excitons in alkali halides. PHYSICAL REVIEW. B, CONDENSED MATTER 1993; 47:6226-6240. [PMID: 10004586 DOI: 10.1103/physrevb.47.6226] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Kusaka H, Homma Y, Ogasawara H, Munakata M, Tanimura K, Ukita H, Denzumi N, Kawakami Y. Five-year follow-up of Micropolyspora faeni antibody in smoking and nonsmoking farmers. THE AMERICAN REVIEW OF RESPIRATORY DISEASE 1989; 140:695-9. [PMID: 2782740 DOI: 10.1164/ajrccm/140.3.695] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
To examine factors that influence changes in Micropolyspora faeni (MF) antibody titer in farmer's lung disease (FLD), we followed for 5 yr the prevalence of serum MF antibody and the epidemiologic factors (years on farm, hours in barn, and hay-handling time) among 92 dairy farmers in Hokkaido, Japan. The prevalence of MF antibody among nonsmokers was significantly higher than that among smokers: 27.1% versus 7.7% in 1979, 31.3% versus 2.9% in 1984. There was no remarkable change in overall prevalences of MF antibody between 1979 and 1984 (18.5 and 19.6%, respectively). However, out of 17 seropositive farmers, six (35%) became seronegative, and out of 75 seronegative farmers, seven (9.3%) became seropositive after 5 yr. The nonsmoking farmers who remained seronegative throughout the follow-up period were older and had worked longer on farms than the farmers with seroconversion. These results suggest that in addition to smoking habits, age and exposure time to MF influence the immune response to MF in dairy farmers. Out of 11 farmers who remained seropositive throughout the 5-yr period, two (18.2%) developed FLD. Therefore, continuously positive MF antibody is one of the risk factors in the development of FLD.
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Fukae J, Tanimura K, Atsumi T, Koike T. Sonographic synovial vascularity of synovitis in rheumatoid arthritis. Rheumatology (Oxford) 2013; 53:586-91. [DOI: 10.1093/rheumatology/ket311] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Takahashi K, Tanimura K, Honda M, Kikuno M, Toei H, Hyodoh H, Furuse M, Yamada T, Aburano T. Venous sac embolization of pulmonary arteriovenous malformation: preliminary experience using interlocking detachable coils. Cardiovasc Intervent Radiol 1999; 22:210-3. [PMID: 10382051 DOI: 10.1007/s002709900368] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
PURPOSE To evaluate the indication and advantages of venous sac embolization of pulmonary arteriovenous malformations (PAVMs) using interlocking detachable coils (IDCs). METHODS We performed percutaneous embolization in 12 PAVMs in four patients using IDCs, initially placed in the venous sac or at the feeding artery to prevent systemic migration of additional coils. We placed the IDCs in the venous sac in PAVMs with the following vascular architecture: the draining vein was larger than the feeding arteries and both vessels were interposed with the venous sac or there were short feeding arteries. RESULTS Complete occlusion was achieved in all 12 PAVMs without significant complications. We deployed IDCs in the venous sac in eight PAVMs and in the feeding artery in four. CONCLUSION Venous sac embolization may be beneficial in PAVMs with large out-flow vessels or short feeding arteries. IDCs are suitable for this procedure.
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Skuja L, Suzuki T, Tanimura K. Site-selective laser-spectroscopy studies of the intrinsic 1.9-eV luminescence center in glassy SiO2. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 52:15208-15216. [PMID: 9980874 DOI: 10.1103/physrevb.52.15208] [Citation(s) in RCA: 28] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Tanimura K, Halliburton LE. Polarization of the x-ray-induced blue luminescence in quartz. PHYSICAL REVIEW. B, CONDENSED MATTER 1986; 34:2933-2935. [PMID: 9940004 DOI: 10.1103/physrevb.34.2933] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
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Tanimura K, Kawai T, Sakata T. Electronic structure of a porphyrin solid film and energy transfer at the interface with a metal substrate. ACTA ACUST UNITED AC 2002. [DOI: 10.1021/j100444a012] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Tokizaki T, Makimura T, Akiyama H, Nakamura A, Tanimura K, Itoh N. Femtosecond cascade-excitation spectroscopy for nonradiative deexcitation and lattice relaxation of the self-trapped exciton in NaCl. PHYSICAL REVIEW LETTERS 1991; 67:2701-2704. [PMID: 10044495 DOI: 10.1103/physrevlett.67.2701] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
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Tanimura K, Sibley WA, DeShazer LG. Optical properties of Cu+ ions in RbMgF3 crystals. PHYSICAL REVIEW. B, CONDENSED MATTER 1985; 31:3980-3987. [PMID: 9936299 DOI: 10.1103/physrevb.31.3980] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/11/2023]
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Tanimura K, Katoh T, Itoh N. Lattice relaxation of highly excited self-trapped excitons in CaF2. PHYSICAL REVIEW. B, CONDENSED MATTER 1989; 40:1282-1287. [PMID: 9991955 DOI: 10.1103/physrevb.40.1282] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Ozeki K, Ichikawa T, Takehara H, Tanimura K, Sato M, Yaginuma H. Studies on antiallergy agents. III. Synthesis of 2-anilino-1,6-dihydro-6-oxo-5-pyrimidinecarboxylic acids and related compounds. Chem Pharm Bull (Tokyo) 1989; 37:1780-7. [PMID: 2572333 DOI: 10.1248/cpb.37.1780] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
A series of 2-anilino-1,6-dihydro-6-oxo-5-pyrimidinecarboxylic acids with various substituents was synthesized and evaluated in the rat passive cutaneous anaphylaxis test for antiallergic activity. High activity by intraperitoneal and oral administrations was observed for the 3-trifluoromethyl and 2-alkoxyanilino derivatives (64, 79, 81, 82 and 85). Structure-activity relationships are discussed.
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Takahashi H, Ohara S, Yamada M, Ikuta F, Tanimura K, Honda Y. Esthesioneuroepithelioma: a tumor of true olfactory epithelium origin. An ultrastructural and immunohistochemical study. Acta Neuropathol 1987; 75:147-55. [PMID: 3434222 DOI: 10.1007/bf00687075] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
A case of esthesioneuroepithelioma was investigated ultrastructurally and immunohistochemically, using antibodies against neurofilament protein (NFP), glial fibrillary acidic protein (GFAP), keratin, neuron-specific enolase (NSE), S-100 protein (S-100), and tyrosine hydroxylase (TH). The tumor initially manifested as an epidural mass in the anterior cranial fossa in a 64-year-old man, and about 3 1/2 years later, autopsy further revealed extensive metastases to the lymph nodes of the neck and thoracic cavity. In the cranial and nasal cavities, the tumor was composed of fairly uniform, ill-defined cells arranged in nests which were surrounded by a fibrovascular stroma. These histological features were reproduced in the metastatic tumor nodules with frequent occurrence of tubular arrangements of the tumor cells. Ultrastructurally, two different cell types were well recognized by their characteristic morphological features, which were reminiscent of sensory neurons and sustentacular cells of the olfactory epithelium. No dense-cored secretory granules were observed in the tumor cells. Immunohistochemically, the tumor showed a variable number of cells positive for NFP, keratin, NSE and S-100. NFP was present in a relatively small number of cells, which were found diffusely in the nests. Keratin was observed in the cells mainly located at the periphery. NSE-positive cells tended to form irregular clusters in the center. A few S-100-positive cells were found, without any particular arrangement.(ABSTRACT TRUNCATED AT 250 WORDS)
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Case Reports |
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Shibata T, Iwai S, Tokizaki T, Tanimura K, Nakamura A, Itoh N. Femtosecond spectroscopic studies of the lattice relaxation initiated by interacting electron-hole pairs under relaxation in alkali halides. PHYSICAL REVIEW. B, CONDENSED MATTER 1994; 49:13255-13258. [PMID: 10010253 DOI: 10.1103/physrevb.49.13255] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Shluger AL, Puchin VE, Suzuki T, Tanimura K, Itoh N. Optical transitions of the H centers in alkali halides. PHYSICAL REVIEW. B, CONDENSED MATTER 1995; 52:4017-4028. [PMID: 9981528 DOI: 10.1103/physrevb.52.4017] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/12/2023]
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Kusaka H, Ogasawara H, Munakata M, Tanimura K, Ukita H, Denzumi N, Homma Y, Kawakami Y. Two-year follow up on the protective value of dust masks against farmer's lung disease. Intern Med 1993; 32:106-11. [PMID: 8507920 DOI: 10.2169/internalmedicine.32.106] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Some advocate moving away from the farm environment for farmers affected with farmer's lung disease (FLD), but most affected farmers still live on farms. In this study, we evaluated the practicality of dust masks and their effectiveness in prevention of FLD. The dust masks we chose were practically used and no new severe episodes of FLD developed in 20 of 21 farmers with FLD using the masks during a 2-year period. When the farmers took off the dust masks in a farming environmental provocation test, statistically significant reductions in FVC (mean 3.43 to 3.351, p < 0.01), DLco (mean 19.6 to 18.2 ml/torr/min, p < 0.01), and DL/VA (mean 5.1 to 4.8 (x10(-3)) 1/torr/min, p < 0.01) were observed several hours after exposure. These findings suggest that the dust masks were used practically during routine dairy farming and were effective in protection against FLD.
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Tanimura K, Suzuki T, Itoh N. Resonance Raman scattering of the self-trapped exciton in alkali halides. PHYSICAL REVIEW LETTERS 1992; 68:635-638. [PMID: 10045951 DOI: 10.1103/physrevlett.68.635] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
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Sjakste J, Tanimura K, Barbarino G, Perfetti L, Vast N. Hot electron relaxation dynamics in semiconductors: assessing the strength of the electron-phonon coupling from the theoretical and experimental viewpoints. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2018; 30:353001. [PMID: 30084390 DOI: 10.1088/1361-648x/aad487] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The rapid development of the computational methods based on density functional theory, on the one hand, and of time-, energy-, and momentum-resolved spectroscopy, on the other hand, allows today an unprecedently detailed insight into the processes governing hot-electron relaxation dynamics, and, in particular, into the role of the electron-phonon coupling. Instead of focusing on the development of a particular method, theoretical or experimental, this review aims to treat the progress in the understanding of the electron-phonon coupling which can be gained from both, on the basis of recently obtained results. We start by defining several regimes of hot electron relaxation via electron-phonon coupling, with respect to the electron excitation energy. We distinguish between energy and momentum relaxation of hot electrons, and summarize, for several semiconductors of the IV and III-V groups, the orders of magnitude of different relaxation times in different regimes, on the basis of known experimental and numerical data. Momentum relaxation times of hot electrons become very short around 1 eV above the bottom of the conduction band, and such ultrafast relaxation mechanisms are measurable only in the most recent pump-probe experiments. Then, we give an overview of the recent progress in the experimental techniques allowing to obtain detailed information on the hot-electron relaxation dynamics, with the main focus on time-, energy-, and momentum-resolved photoemission experiments. The particularities of the experimental approach developed by one of us, which allows to capture time-, energy-, and momentum-resolved hot-electron distributions, as well as to measure momentum relaxation times of the order of 10 fs, are discussed. We further discuss the main advances in the calculation of the electron-phonon scattering times from first principles over the past ten years, in semiconducting materials. Ab initio techniques and efficient interpolation methods provide the possibility to calculate electron-phonon scattering times with high precision at reasonable numerical cost. We highlight the methods of analysis of the obtained numerical results, which allow to give insight into the details of the electron-phonon scattering mechanisms. Finally, we discuss the concept of hot electron ensemble which has been proposed recently to describe the hot-electron relaxation dynamics in GaAs, the applicability of this concept to other materials, and its limitations. We also mention some open problems.
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