‫ ی‬M&BE ◊✲఍(M&BE, Vol.34, No.2 (2023))(ཎ✏ཷ⌮᪥㸸2023 ᖺ 5 ᭶ 10 ᪥)ࠕḟୡ௦࡟ྥࡅࡓ᭷ᶵศ猖࣭ࣂ࢖࢚࢜ࣞࢡࢺࣟࢽࢡࢫ᭱᪂◊✲ࠖ⾲㠃ሙࢆ⏝࠸ࡓ᪂ࡓ࡞పḟඖศᏊ☢ᛶయࡢ㛤Ⓨ༓ⴥ኱Ꮫ ኱Ꮫ㝔ᕤᏛ◊✲㝔 ≀㉁⛉Ꮫࢥ࣮ࢫ༓ⴥ኱Ꮫ ศᏊ࢟ࣛࣜࢸ࢕࣮◊✲ࢭࣥࢱ࣮ ᒣ⏣ ㇏࿴toyoyamada@faculty.chiba-u.jp
1. ࡣࡌࡵ࡟ 㑄⛣㔠ᒓ࢖࢜ࣥࡢ࿘ᅖ࡟㓟⣲ཎᏊࡸ❅⣲ཎᏊࠊࡲࡓࡣ࢝ࣝࢥࢤࣥඖ⣲ࡸࣁࣟࢤࣥඖ⣲ࡢཎᏊࢆᑐ⛠ⓗ࡟㓄఩ࡍࡿ஦࡛ࠊ㔞Ꮚࢫࣆࣥᾮయ 1,2)ࡸཎᏊᒙ☢ᛶయ 3,4)࡞࡝ࠊ᪂ࡓ࡞㔞Ꮚࢫࣆࣥᮦᩱࡸ☢ᛶ≀㉁ࢆ㛤Ⓨࡍࡿ஦ࡀ࡛ࡁࡿࠋࡇࢀࡽࡣ୺࡟஧ḟඖᖹ㠃ཎᏊᒙࡀ✚ᒙࡋࡓ୕ḟඖࣂࣝࢡ⤖ᬗࢆྜᡂࡍࡿࡇ࡜࡛㛤Ⓨࡀ㐍ࡵࡽࢀ࡚ࡁࡓࠋ
୍᪉ࠊ࣎ࢺ࣒࢔ࢵࣉᡭἲ࡛ࡶࡇࡢࡼ࠺࡞୍ḟඖࡸ஧ḟඖࢼࣀᵓ㐀యࢆ㛤Ⓨࡍࡿ◊✲ࡶ
㏆ᖺάⓎ໬ࡋ࡚࠸ࡿࠋ࠸ࢃࡺࡿ⾲㠃ྜᡂ࡛࠶ࡿ 5–7)ࠋ୙⣧≀ࡀᴟࡵ࡚ᑡ࡞࠸㉸㧗┿✵⎔ቃ࡟࠾࠸࡚ࠊཎᏊ࡛ࣞ࣋ࣝᖹᆠ࡞ᇶᯈ⾲㠃ୖ࡟๓㥑యศᏊࢆ྾╔ࡋࠊ⮬ᕫ⤌⧊໬ࡲࡓࡣຍ⇕࡟ࡼࡿ࣐࢘ࣝࣥ཯ᛂࢆ⏝࠸࡚ࠊcovalent organic framework (COF)ࡸ㔠ᒓཎᏊࢆྲྀࡾ㎸ࢇࡔmetal organic framework (MOF)ࡀస〇࡛ࡁࡿࠋࡇࡢࡼ࠺࡞༢ศᏊࣞ࣋ࣝࡢ࣑ࢡࣟ࡞ྜᡂࢆࠊ┤᥋ほᐹ࡛ࡁ࡞࠸࠿㸽ࡇࢀࢆᐇ⌧ࡍࡿࡢࡀࠊᡃࠎࡢ◊✲ᐊ࡛ࠊ㐣ཤ 20 ᖺ⮬స㛤Ⓨࡋ࡚ࡁࡓ㉮ᰝࢺࣥࢿࣝ㢧ᚤ㙾 (scanning tunneling microscopy: STM)࡛࠶ࡿࠋཎᏊศᏊ୍ಶࢆ┤᥋ほᐹ࡛ࡁࡿࠋ≉࡟ࠊSTM ほᐹࡋ࡞ࡀࡽࠊࡑࡢሙ࡛ศᏊヨᩱࡢ㟁Ꮚ≧ែ (HOMO/LUMO)ᐃࡀྍ⬟࡞㉮ᰝࢺࣥࢿࣝศගἲ (scanning tunneling spectroscopy)ࢆⓎᒎࡉࡏ࡚ࡁࡓࠋࡉࡽ
࡟ࠊࢫࣆࣥ೫ᴟ STM ᥈㔪ࢆά⏝ࡍࡿ஦࡛ࠊ༢୍᭷ᶵศᏊ☢▼ࡢ㟁Ꮚࢫࣆࣥ≧ែࡢ┤᥋ほᐹࢆ⾜ࡗ࡚ࡁࡓ 8–18)ࠋࡇࡢᡭἲࡣࠊࢫࣆࣥ೫ᴟ STM/STS ࡜࿧ࡤࢀࡿࠋࡉࡽ࡟⌧ᅾࠊSTM ⿦⨨࡟ගࣇ࢓࢖ࣂ࣮ࢆᑟධࡋࠊᅗ 1 ࡟♧ࡍග↷ᑕ/᳨ฟᶵᵓࢆ⤌ྜࡏࠕศᏊя☢ᛶࢫࣆࣥяගࠖࡢ࣑ࢡࣟ࡞┦஫స⏝ࡢゎ᫂࡟ᣮᡓࡋ࡚࠸ࡿࠋ
2. ༢୍᭷ᶵศᏊࡢ STM ほᐹ࡜ࡑࡢሙ࡛ࡢ㟁ᏊศගィཎᏊศゎ⬟ࢆ᭷ࡍࡿ STM ࡣࠊ㸯ಶࡢ᭷ᶵศᏊࡢᵓ㐀ほᐹ࡟㐺ࡋࡓᡭἲ࡛࠶ࡿࠋᅗ 1 ࡟ STM ᐃࡢᴫせᅗࢆ♧ࡍࠋSTM ほᐹࡍࡿࡓࡵ࡟ࡣࠊᑐ㇟≀ࢆᇶᯈ⾲㠃࡟ᅛᐃࡋࠊࡑࡢヨᩱ⾲㠃ࡢ⣙ 0.5-1.0 nm ୖࢆ᥈㔪ඛ➃ࡀ㉮ᰝࡍࡿࠋ᥈㔪࡜ヨᩱ㛫࡟ࡣࢺࣥࢿࣝ㟁ὶࢆὶࡋࠊࢺࣥࢿࣝ㟁ὶࢆィ ࡍࡿ஦࡛ࠊ㧗ࡉ᝟ሗࡸヨᩱ㟁Ꮚ≧ែᐦᗘࡀィ ࡛ࡁࡿࠋᇶᯈస〇࡟ࡶὀពࢆせࡍࡿࠋཎᏊศゎ⬟ࢆᚓࡿࡓࡵ࡟ࡣࠊศᏊࢆ྾╔ࡍࡿᇶᯈ⾲㠃ࡀࠊཎᏊ࡛ࣞ࣋ࣝᖹᆠ໬࠿ࡘΎί࡛࡞ࡃ࡚ࡣ࡞ࡽ࡞࠸ࠋSTM ࡛ࡣᇶᯈ⾲㠃࡟྾╔ࡋࡓ୙⣧≀ศᏊࡶほᐹ࡛ࡁ࡚ࡋࡲ࠺ࡓ670୵ਓޭ‫ݗ‬ड़φϱϋϩుࢢޭলࣻࢾྋ༙‫ؽ‬෾ࢢ

ᅗ 1 STM ᴫせᅗ㸫56 (25)㸫

ࡵࠊ✵Ẽ୰࡟ᏑᅾࡍࡿศᏊࡣ඲࡚୙⣧≀ศᏊ࡜࡞ࡿࠋࡑࡢࡓࡵࠊ㉸㧗┿✵⎔ቃࡀᚲせ࡜࡞ࡿࠋ㉸㧗┿✵⎔ቃୗ࡛Ύί࡞ᇶᯈ⾲㠃ࢆ‽ഛࡋࠊࡇࡢ⾲㠃࡟ほᐹࡋࡓ࠸᭷ᶵศᏊࢆ྾╔ࡍࡿࠋᇶᯈ࡜ศᏊࢆࡘ࡞ࡂ࡜ࡵࡿࡢ࡟ᗈࡃ⏝࠸ࡽࢀࡿࡢࡀࠊᇶᯈ࡜ศᏊ㛫ࡢ van der Waals ᘬຊ࡛࠶ࡿࠋࡇࡢᘬຊࡣศᏊࡀᇶᯈ⾲㠃࠿ࡽ⬺㞳ࡍࡿࡢࢆ㜵ࡄࡔࡅࡢຊࡣ࠶ࡿࡀࠊᐊ ࡛ࡣᇶᯈ⾲㠃ୖࢆศᏊࡀ⇕ᣑᩓࡍࡿࡇ࡜ࢆṆࡵࡽࢀ࡞࠸ࠋࡑࡢࡓࡵࠊከࡃࡢศᏊࡣࠊ⇕ᣑᩓࡋ⮬ᕫ⤌⧊໬⭷ࢆᙧᡂࡋ࡚ࡋࡲ࠸ࠊ༢୍ศᏊ࡜ࡋ࡚ほᐹࡍࡿࡇ࡜ࡀ࡛ࡁ࡞࠸ࠋࡑࡢࡓࡵࠊ㸯ಶࡢ᭷ᶵศᏊほᐹ࡟ࡣࠊࡉࡽ࡟ప ⎔ቃࡶᚲせ࡜࡞ࡿࠋ㉸㧗┿✵⎔ቃ STM ඲యࢆࢡࣛ࢖࢜ࢫࢱࢵࢺ෭෾ᶵ࡛෭༷ࡍࡿᡭἲࡀᗈࡃ౑
⏝ࡉࢀࡿࠋ㉸㧗┿✵࣭ᴟప (4.6 K)⎔ቃ࡛ࡢ༢୍᭷ᶵศᏊࡢ STM/STS ࡢ౛ࢆᅗ 2 ࡟♧ࡍࠋMgO ⤯⦕⭷ୖ࡟྾╔ࡋࡓ㖡ࣇࢱࣟࢩ࢔ࢽࣥ(CuPc)༢୍ศᏊࢆほᐹࡋࡓ 19)ࠋᕥᅗࡢ STM ീ (ヨᩱ㟁ᅽ -2 V)ࡣࠊศᏊ HOMO ㌶㐨ࡢ✵㛫ศᕸࢆ♧ࡍࠋSTM ീ୰࡟᫂ࡿࡃぢ࠼࡚࠸ࡿ㒊ศ࡟
HOMO ㌶㐨ࡀᒁᅾࡋ࡚࠸ࡿࠋ୰ኸᅗࡣ CuPc ༢ศᏊୖ࡛ィ ࡋࡓ STS ᭤⥺࡛࠶ࡿࠋࣇ࢙࣑ࣝ‽఩㏆ഐࡢᚤศఏᑟ dI/dV ್ࡀ 0 nA/V ࡛࠶ࡿࡇ࡜ࡣࠊศᏊࡀࢠࣕࢵࣉࢆᣢࡘ༙ᑟయ࡛࠶ࡿࡇ࡜ࢆព࿡ࡍࡿࠋࡲࡓ MgO ⤯⦕⭷ࡀ Fe(001)ᇶᯈ࡜ࡢ㟁Ꮚⓗ⤖ྜࢆษࡿ(=decouple)ᙺ๭ࢆᯝࡓࡋࠊ࢞ࢫ≧ែ࡟㏆࠸ CuPc ༢୍ศᏊࢆᇶᯈ⾲㠃ୖ࡛ほᐹ࡛ࡁ࡚࠸ࡿࡇ࡜ࡶព࿡ࡍࡿࠋHOMO ࡜ LUMO ࣆ࣮ࢡࡀࠊࡑࢀࡒࢀࣇ࢙࣑ࣝ‽఩ (EF)ࡢୗ-1 eV ࡜ୖ+1 eV ࡟ほࡉࢀࡓࠋྑᅗࡣࠊ➨୍ཎ⌮ィ⟬࡟ࡼࡿ MgO ⭷ୖࡢ CuPc ศᏊࡢ㟁Ꮚ≧ែᐦᗘࢆ♧ࡋࠊƵWĐ ͬDŐKĨŝůŵƐǆƉ͘Ăů͘㻣㻰㻻㻿㻔㼟㼜㼕㼚㻙㼡㼜㻕㻰㻻㻿㻔㼟㼜㼕㼚㻙㼐㼛㼣㼚㻕㻢㻟㻜㻠㻞㻜㻰㻻㻿㼐㻵㻛㼐㼂㻌㼇㼜㻭㻛㼂㼉㻡㻟
㻞

,KDK㻝
㻜

>hDK㻝㻜ĞĐŽƵƉůŝŶŐ㻜䌦㻝䌦㻝㻚㻡䌦㻝㻚㻜䌦㻜㻚㻡㻜㻚㻜㻜㻚㻡㻝㻚㻜㻝㻚㻡䌦㻝㻚㻡㻱㻌㻙㻌㻱㻲㻌㼇㼑㼂㼉䌦㻝㻚㻜䌦㻜㻚㻡㻜㻚㻜㻜㻚㻡㻝㻚㻜㻝㻚㻡㻱㻌㻙㻌㻱㻲㻌㼇㼑㼂㼉ᅗ 2 㖡ࣇࢱࣟࢩ࢔ࢽࣥ(CuPc)༢୍ศᏊࡢ STM ほᐹ࡜ STS 㟁Ꮚศග࡟ࡼࡿࡑࡢሙ࡛ࡢ
ศᏊ㌶㐨ィ ࠋᇶᯈࡣࠊ㓟⣲ࢥ࣮ࢺࡋࡓ Fe(001)-p(11)O ⾲㠃࡟ᡂ㛗ࡋࡓ MgO ⤯⦕⭷ࢆ౑⏝ࠋᕥ࠿ࡽᙧ≧ീࠊࣇ࢙࣑ࣝ‽఩㏆ഐࡢ HOMO/LUMO ィ ࡢᐇ㦂࡜ィ⟬⤖ᯝࠋᐇ㦂⤖ᯝ࡜୍⮴ࡍࡿ఩⨨࡟ HOMO/LUMO ࣆ࣮ࢡࢆ♧ࡋࡓ 19)ࠋ3. ⾲㠃ྜᡂ࡟ࡼࡿపḟඖศᏊ᱁Ꮚࡢస〇࡜᪂ࡓ࡞☢▼㛤Ⓨ࡬ᡃࠎࡣࠊᇶᯈ⾲㠃࡜࠸࠺ࢺ࣏ࣟࢪ࢝ࣝⓗ࡟ࣘࢽ࣮ࢡ࡞⣔࡛ࡢ஧ḟඖ㔞Ꮚࢫࣆࣥ᱁Ꮚࡢ㛤Ⓨ࡟ᣮᡓࡋ࡚࠸ࡿࠋࡇࢀࡲ࡛ࠊ㔞Ꮚࢫࣆࣥᾮయ 1,2)ࡸཎᏊᒙ☢ᛶయ 3,4)࡞࡝ࡢᮦᩱࡣ୺࡟ࣂ
ࣝࢡ⤖ᬗྜᡂἲࢆ⏝࠸࡚㛤Ⓨࡉࢀ࡚ࡁࡓࠋᡃࠎࡢ࢔ࣉ࣮ࣟࢳࡣ␗࡞ࡿࠋ࣎ࢺ࣒࢔ࢵࣉ࡛ࠊ⣲ᮦ࡜࡞ࡿ༢୍ศᏊࢆᇶᯈ⾲㠃ୖ࡟྾╔

㸫57 (26)㸫

ࡋࠊࡇࢀࢆ⾲㠃ୖ࡛࣐࢘ࣝࣥ཯ᛂ➼ࡢ໬Ꮫ཯઴ۨର෾ࢢʹ̔‫ݺ‬ʻ࿣ֱ‫ܙ‬
7ULVEHQ]HQHBrBrᛂ࡟ࡼࡾ⤖ྜࡉࡏࠊ᪂ࡓ࡞ MOF స〇ࢆ⾜࠺ࠋBrBr ᅗ 3 ࡟ STM ࡟ࡼࡿ⾲㠃ྜᡂ◊✲ࡢ୍౛ࢆ
BrBr x2+ЉQP݂
୦཯Br♧ࡍࠋࡇࡇ࡛ࡣ Au(001)ᇶᯈࢆ౑⏝ࡋࡓࠋ㉸
BrBr㧗┿✵⎔ቃෆ࡛ᖹᆠ໬࡜Ύί໬ࡋࡓ Au(001)
BrBr⾲㠃ࢆᇶᯈ࡜ࡋ࡚⏝࠸ࡓࠋᇶᯈ ᗘ 300 K ࡟࡚ࠊࢺࣜࢫ࣋ࣥࢮࣥ๓㥑యศᏊࢆ྾╔ࡋࠊ⥆ࡅ࡚ຍ⇕ࡋࡓࠋࡍࡿ࡜ࠊᅗ 3 ୖഃࡢࣔࢹࣝᅗࡀ♧ࡍࡼ࠺࡟ࠊࢺࣜࢫ࣋ࣥࢮࣥ⤊➃ࡢ⮯⣲ཎᏊࡀ⬺㞳ࡋࡓࠋ⮯⣲ཎᏊࡀ࡞ࡃ࡞ࡾࠊ࣋ࣥࢮ
ࣥ⎔࠿ࡽఙࡧࡿᡭࡀ࠶࠸ࡓ๓㥑యศᏊྠኈ
ࡀᇶᯈ⾲㠃ୖ࡛⇕ᣑᩓࡋูࡢ๓㥑యศᏊ࡜ฟ఍ࡗࡓ㝿ࠊ㐠ࡼࡃ஧ࡘࡢ๓㥑యศᏊࡢᡭࡀඹ࡟✵࠸࡚࠸ࢀࡤ᪂ࡓ࡞ඹ᭷⤖ྜࡀ⏕ࡌࠊ஧ࡘࡢ๓㥑యศᏊࡣ⤖ྜࡋࡓࠋࡇࡢࣉࣟࢭࢫࡀ
⧞ࡾ㏉ࡉࢀࠊᅗ 3 ࡢࣔࢹࣝ࡟♧ࡍභゅᙧࡢከ QP
Ꮝ㉁᱁Ꮚࡀ࡛ࡁࡓࠋ
ᅗ 3 ୗᅗ࡟ࠊᐇ㝿࡟స〇ࡋࡓ COF ᱁Ꮚࡢ ᅗ 3 ๓㥑యศᏊࢆ⏝࠸ࡓ⾲㠃ྜᡂ࡟ࡼ
STM ീࢆ♧ࡍࠋᩘ nm ࠿ࡽᩘ༑ nm ࢧ࢖ࢬࡢ ࡿ஧ḟඖศᏊ᱁Ꮚࡢస〇ࠋCOF ⭷ࡣసᡂ࡛ࡁࡓࡀࠊᆒ୍࡞ᙧ≧ࡢ᱁Ꮚࡢస〇ࡣᅔ㞴࡛࠶ࡿࡇ࡜ࡶศ࠿ࡗࡓࠋࡉࡽ࡟ࡇࡢ᱁Ꮚ࡟☢ᛶ㔠ᒓࢥࣂࣝࢺࢆ⵨╔ࡋࡓࠋࡋ࠿ࡋࠊศᏊ࡜☢ᛶ㔠ᒓࡣỈ࡜Ἔࡢࡼ࠺࡟ศ㞳ࡋ࡚ᡂ㛗ࡋࡓࠋ༢⣧࡟ࠊඹ᭷⤖ྜࡋࡓ᭷ᶵᵓ㐀య࡟☢ᛶ㔠ᒓࢆ྾╔ࡋ࡚ࡶ⼥ྜࡋ࡞࠸஦ࡀศ࠿ࡗࡓࠋ
ᅗ 3 ࡢ⤒㦂ࢆ㋃ࡲ࠼ࠊ⌧ᅾࠊ☢ᛶཎᏊࡀ⤌ࡳ㎸ࡲࢀࡿࡼ࠺࡟⣽ᕤࢆ᪋ࡋࡓ๓㥑యศᏊࢆ⏝࠸࡚ࠊ᪂ࡓ࡞పḟඖศᏊ☢ᛶᵓ㐀యࢆ㛤Ⓨࡋ࡚࠸ࡿࠋヲ⣽ࢆሗ࿌ࡍࡿࠋ
4. ࡲ࡜ࡵཎᏊศゎ⬟ࡢ㧗࠸✵㛫ศゎ⬟ࢆ᭷ࡍࡿ㉮ᰝࢺࣥࢿࣝ㢧ᚤ㙾(STM)࡜ࠊ1 meV ௨ୗࡢ㧗࠸࢚ࢿࣝࢠ࣮ศゎ⬟ࢆᣢࡘ㉮ᰝࢺࣥࢿࣝศග(STS)ࢆ㥑౑ࡍࡿ஦࡛ࠊ᪂ࡓ࡞పḟඖศᏊ☢▼ࡢ
㛤Ⓨ࡟ᣮᡓࡋ࡚࠸ࡿࠋᇶᯈ⾲㠃ୖ࡛ࠊ⣲ᮦ࡜࡞ࡿ๓㥑యศᏊ࡜☢ᛶཎᏊࢆ┤᥋ࡑࡢሙほᐹࡋ࡞ࡀࡽ⤌ࡳୖࡆ࡚࠸ࡃࠋศᏊࢆ௓ࡍࡿ☢ᛶཎᏊ㛫ࡢ☢Ẽ⤖ྜࡢゎ᫂ࢆ㏻ࡋ࡚ࠊཎᏊᒙ☢
▼ࡸ㔞Ꮚࢫࣆࣥᾮయ➼ࡢ☢Ẽࣇࣛࢫࢺ࣮ࣞࢩࣙࣥ⣔ࡢᵓ⠏ࢆ⾲㠃ሙ࡛┠ᣦࡍࠋᮏ◊✲ࡣࠊ(⊂)᪥ᮏᏛ⾡᣺⯆఍⛉Ꮫ◊✲㈝⿵ຓ㔠ᣮᡓⓗⴌⱆࠊබ┈㈈ᅋἲே࢝ࢩ࢜⛉Ꮫ᣺⯆㈈ᅋࠊᯇ
⡱⛉Ꮫᢏ⾡᣺⯆㈈ᅋࠊᮾ㟁グᛕ㈈ᅋࠊᑠ➟ཎᩄᬗグᛕ㈈ᅋ࠿ࡽࡢຓᡂࡢୗࠊᐇ᪋࡛ࡁࡓࠋ
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