᪂Ꮫ⾡㡿ᇦ◊✲䛂≀㉁䝕䝄䜲䞁䛃䜻䝑䜽䜸䝣䞉䝭䞊䝔䜱䞁䜾A03㧗㧗⏣⌜➨୍ཎ⌮⣔ບ㉳≧ែࡢከయㄽ࡜㧗㌿⛣ ᗘ㉸ఏᑟ≀㉁ࢹࢨ࢖ࣥ
௦⾲㸸 㧗⏣ᗣẸ 㸦ᮾ኱≀ᛶ◊㸧ศᢸ㸸 ⓑ஭ග㞼 㸦㜰኱⏘◊㸧๓ᅬᾴ㸦໭㝣ඛ➃኱᝟ሗ⛉Ꮫ㸧๓ᶫⱥ᫂ 㸦ᮾ኱≀ᛶ◊㸧ྜྷ⃝㤶ዉᏊ㸦ୖᬛ኱⌮ᕤ㸧㐃ᦠ㸸 ᩪ⸨᫴㸦ᮾᕤ኱⌮ᕤ㸧኱㔝࠿࠾ࡿ㸦ᶓᅜ኱ᕤ㸧᫝ᖖ㝯㸦ᮾᕤ኱⌮ᕤ㸧⛅ග⣧㸦㟷Ꮫ኱⌮ᕤ㸧᫓ᒣ⣧ᚿ 㸦㟷Ꮫ኱⌮ᕤ㸧ୖ⏣ᐶ㸦ᮾ኱≀ᛶ◊㸧ᘅ஭ၿ஧ 㸦ᮾ኱≀ᛶ◊㸧ᖺ᭶᪥᪊ᮾ኱ᕤྕ㤋ྕㅮ⩏ᐊ➨୍ཎ⌮䛛䜙䛾ከయ⌮ㄽ䠄㧗⏣⌜䠅1➨୍ཎ⌮䛛䜙䛾ከయ⌮ㄽ䠖ᇶᮏㄆ㆑㟁Ꮚ䝃䜲䝗䛛䜙ぢ䛯➨୍ཎ⌮䛾䝝䝭䝹䝖䝙䜰䞁䝹䝖 䜰䞁Æ 䠄䝣䜷䝜䞁䛸䛾┦஫స⏝䜒ྵ䜑䛶䠅 ୙ᆒ୍ᐦᗘ䛾㟁Ꮚ䜺䝇⣔≀㉁䛾ከᵝᛶ Å ከᙬ䛺୙ᆒ୍ᛶᇶᮏㄆ㆑䖂ከᙬ䛺୙ᆒ୍ᛶ䜢⤫୍ⓗ䛻ྲྀ䜚ᢅ䛖ᡭἲ Æ ᐦᗘỗ㛵ᩘἲ䖂≉ᐃ䛾≀⌮㔞䠄n(r)䜔Tc䠅䜢䠄௚䛾≀⌮㔞䛾⢭ᗘ䛸䛿㛵ಀ䛺䛟䠅ᙧᘧୖཝᐦ䛻Ỵᐃ䛷䛝䜛䚹 䠄Æ ≀⌮㔞䛤䛸䛾䝇䜻䞊䝮ᵓᡂ䠅Å 䠄ᐇ㦂䛸ఝ䛯ഃ㠃䛜䛒䜚䚸䠅௚䛾ᡭἲ䛸䛿㝿䛰䛳䛶㐪䛖≉ᚩ䛯䛸䛘䜀䚸 DFT䛷䛿ᇶᗏ≧ែ䜶䝛䝹䜼䞊 E0 䜔ᑐᛂ䛩䜛㟁Ꮚᐦᗘ n(r)䛿ᐦᗘ┦㛵㛵ᩘ gn(r1,…,rn) 䜢඲䛟▱䜙䛺䛟䛶䜒ཝᐦ䛻Ỵ䜑䜙䜜䜛䚹䠄䛯䛸䛘LDA䛷䜒ཎᏊ㛫⤖ྜ㛗䛿1%⛬ᗘ䛾⢭ᗘ䛷Ỵ䜎䜛䚹䠅୍᪉䚸䜾䝸䞊䞁㛵ᩘἲ䛷䛿n(r) 䛸 gn(r1,…,rn) 䛿䛚஫䛔䛻ᐦ᥋䛺㛵㐃䛜䛒䜛 䠄䛔䜟䜖䜛BBGKY㝵ᒙᵓ㐀䛾Ꮡᅾ䠅ᨾ䛻䚸 gn(r1,…,rn) 䛾䜘䛔㏆ఝゎ䛜ồ䜎䜙䛺䛔㝈䜚䚸⢭ᗘ䛾䜘䛔䠄䛭䜜䛷䜒㏆ఝ䛻㐣䛞䛺䛔䠅 n(r) 䛿ồ䜑䜙䜜䛺䛔䚹➨୍ཎ⌮䛛䜙䛾ከయ⌮ㄽ䠄㧗⏣⌜䠅

2➨୍ཎ⌮䛛䜙䛾ከయ⌮ㄽ䠖ᇶᮏᡓ␎
ᇶᮏᡓ␎
䖂DFT䛷㘽䛸䛺䜛≀⌮㔞䠄Vxc䜔fxc䛺䛹䠅䛾ỗ㛵ᩘᙧ䛜ᚲせÆ ୺䛸䛧䛶ᆒ୍ᐦᗘ⣔䛷䛾✀䚻䛾≀⌮㔞䜢䜾䝸䞊䞁㛵ᩘἲᏊ䝰䞁䝔䜹䝹 ィ⟬䛺䛹䛾ከᵝ䛺䛺䜔㔞Ꮚ䝰䞁䝔䜹䝹䝻ィ⟬䛺䛹䛾ከᵝ䛺ከయ⌮ㄽ䛷◊✲Æ 㐺ษ䛺ỗ㛵ᩘᙧ䛾⪃᱌䖂⪃᱌䛥䜜䛯ỗ㛵ᩘᙧ䜢“඾ᆺⓗ䛺”䠄䝰䝕䝹໬䛧䛯䠅୙ᆒ୍⣔䛻㐺⏝䛩䜛䚹䛭䛧䛶䚸௚䛾ᡭἲ䛷ィ⟬䛥䜜䛯⤖ᯝ䛸ẚ㍑䛧䛶䚸
䛭䛾ỗ㛵ᩘᙧ䛾ホ౯䞉ᨵⰋ䜢⾜䛖䚹䖂 㐺ษ䛸ุ᩿䛥䜜䛯ỗ㛵ᩘᙧ䜢ከᙬ䛺୙ᆒ୍⣔䛻㐺⏝䛧䛶䚸⤖ᯝ䜢ᯝ䜢㛵㐃䛩䜛ᐇ㦂䛸ẚ㍑
䜢䜢㛵᳨ウ䛩䜛䚹ᚓ䜙䜜䛯⤖ᯝ䜢㛵㐃䛩䜛ᐇ㦂䛸ẚ㍑䞉᳨ウ䛩䜛䚹Æ 㧗T ≀㉁㛤Ⓨ䜈䛾䝠䞁䝖䜢ᚓ䜛c➨୍ཎ⌮䛛䜙䛾ከయ⌮ㄽ䠄㧗⏣⌜䠅

3➨୍ཎ⌮䛛䜙䛾ከయ⌮ㄽ䠖ලయⓗ䛺┠ᶆලయⓗ䛺┠ᶆ
䖂 Vxc䛻㛵㐃䛧䛶䚸㟁Ꮚ䜺䝇୰䛾䠍ཎᏊ⣔䛾≀⌮䠄⢭ᗘ䛾䜘䛔 n(r)䛾Ỵᐃ䛸㏫䠧䠯ἲ䛻䜘䜛⢭ᗘ䛾㧗䛔 Vxc 䛾ᵓᡂ䠅䠖䠠䠩䠟䠄๓ᅬ䠅䚸䠯䠰䠨䠯䠄ྜྷ⃝䠅䚸䠡䠬䠴䠄㧗⏣䠅
䖂 fxc䛻㛵㐃䛧䛶䚸䝷䝑䝔䜱䞁䝆䝱䞊ὶయ䜢ྵ䜐ᆒ୍ᐦᗘ㟁Ꮚ⣔䜔ᙅ㠀ᆒ୍ᐦᗘ㟁Ꮚ⣔䛷䛾䠍㟁Ꮚ䝇䝨䜽䝖䝹䜔ືⓗ┦㛵㛵ᩘ䠖
䠣䠳*䠄๓ᶫ䠅䚸䠣䠳䛺䛹䛾㛵㐃䛩䜛◊✲㸦ᩪ⸨ࠊ኱㔝㸧䖂 Tc䛻㛵㐃䛧䛶䚸ᆒ୍ᐦᗘ㟁Ꮚ⣔䛷䛾ᙅ⤖ྜ㉸ఏᑟᶵᵓ䠖䠣䠌䠳䠌㏆ఝ䠄ྜྷ⃝䚸㧗⏣䠅
䖂 Tc䛻㛵㐃䛧䛶䚸▷䝁䝠䞊䝺䞁䝇㛗ᙉ⤖ྜ㉸ఏᑟᶵᵓ䠖䜽䝷䝇䝍䞊ィ⟬䠄㧗⏣䠅䚸䜶䝸䜰䝅䝳䝞䞊䜾⌮ㄽィ⟬䛾㛵㐃䛩䜛◊✲䠄᫝ᖖ䠅䚸㛵㐃䛩䜛⌮ㄽண 䠄ⓑ஭䠅䚸䛚䜘䜃䚸㛵㐃䛩䜛ᐇ㦂◊✲䠄⛅ග䚸᫓ᒣ䚸ୖ⏣䚸ᘅ஭䠅➨୍ཎ⌮䛛䜙䛾ከయ⌮ㄽ䠄㧗⏣⌜䠅4㉸ఏᑟ䛾⌮ㄽ◊✲䠖୍䛴䛾኱䛝䛺┠ᶆ‫۔‬㉸ఏᑟయࡢᡂศඖ⣲ࡢ᝟ሗ Æ Tcࡢ㧗⢭ᗘண‫ۑ‬㉸ఏᑟయࢆࡼࡃグ㏙ࡍࡿᚤどⓗ࡞㟁Ꮚ᱁Ꮚࣔࢹࣝࣁ࣑ࣝࢺࢽ࢔ࣥ࠿ࡽ㸦ᨃࢡ࣮࣏ࣟࣥࢸࣥࢩࣕࣝP➼ࡢ⌧㇟ㄽⓗ࡞ࣃ࣓࣮ࣛࢱࢆ୍ษᑟධࡋ࡞࠸㸧┤᥋ⓗ࡞Tcࡢ㧗⢭ᗘணṇᖖ≧ែࡢ≀ᛶࡸ௚ࡢ⛛ᗎ≧ែ࡜ࡢ➇ྜࢆጞࡵ࡜ࡍࡿㅖࠎࡢ㞴ࡋ࠸ࡇ࡜ࢆゎỴࡋࡓᚋ࡛࡞ࡅࢀࡤࠊ㧗⢭ᗘࡢTcィ⟬࡞࡝ฟ᮶࡞࠸ࡣࡎ࡛ࡣ࡞࠿ࡗࡓ࠿㸽Æ ࡇࡢほᛕ࡟ᤕࡽࢃࢀ࡚࠸ࡿ࡜ࠊ࠸ࡘࡲ࡛⤒ࡗ࡚ࡶಙ㢗ᛶࡢ㧗࠸Tcィ⟬ࡣ࡛ࡁ࡞࠸㸟ᚑࡗ࡚ࠊ㧗 ㉸ఏᑟయࡢၥ㢟ゎỴࡣ㸦ࡑࡢ୍␒㔜せ࡞ᛶ㉁ࡣTcࡀ㧗࠸ࡇ࡜࡞ࡢ࡛㸧⤯ᮃⓗ㸟➨୍ཎ⌮䛛䜙䛾ከయ⌮ㄽ䠄㧗⏣⌜䠅5㉸ఏᑟᐦᗘỗ㛵ᩘ⌮ㄽ௚ࡢ≀⌮㔞࡟ࡣὀ┠ࡏࡎࠊ㉸ఏᑟ㌿⛣ࡍࡿ࡜ࡍࢀࡤ
ᑡ࡞ࡃ࡜ࡶࡑࡢTcࡣṇ☜࡟ィ⟬࡛ࡁࡿᐃᘧ໬ࢆ⪃࠼ࡿࠋÆ ㉸ఏᑟࢆྲྀࡾᢅ࠺ࡼ࠺࡟DFTࢆᣑᙇ SCDFTᇶᮏኚᩘ㸸n(r) ࡜ F(r,r’)cf. Oliveira, Gross & Kohn, PRL60, 2430 (1988).

➨୍ཎ⌮䛛䜙䛾ከయ⌮ㄽ䠄㧗⏣⌜䠅6

SCDFT䛾⌧≧2005ᖺ࡟Kijࡢᐇ⏝ⓗ࡞ỗ㛵ᩘᙧࡀᥦ᱌ࡉࢀࡓ

Hardy Gross

cf. Lüders et al., PRB72, 024545 (2005)䕿 䜶䝸䜰䝅䝳䝞䞊䜾⌮ㄽ䛸ྠ⛬ᗘ䜎䛷䛻䝣䜷䝜䞁፹௓ᘬຊ䜢ྲྀ䜚㎸䜑䛯䚹䕿 P*䛾ᴫᛕ䜢⏝䛔䛪䛻䜽䞊䝻䞁᩺ຊ䛾ຠᯝ䜢➨୍ཎ⌮ⓗ䛻ྲྀ䜚㎸䜣䛷Tc 䛜ィ⟬䛷䛝䛯䚹㽢 ᙉ⤖ྜ䝫䞊䝷䝻䞁ຠᯝ䛜ධ䜙䛺䛔䚹㽢 䜽䞊䝻䞁᩺ຊ䛸䝣䜷䝜䞁፹௓ᘬຊ䛾ྲྀ䜚ᢅ䛔䛜ྠ➼䛷䛿䛺䛔䚹㽢 䝇䝢䞁ᦂ䜙䛞䜢ྵ䜐ዴఱ䛺䜛ᶵᵓ䛷䛒䜜䚸䜽䞊䝻䞁᩺ຊ㉳※䛾㉸ఏᑟᶵᵓ䛜㆟ㄽฟ᮶䛺䛔䚹䜒䛳䛸䜘䛔Kij䛾ỗ㛵ᩘᙧ䜢᥈䛭䛖!!
➨୍ཎ⌮䛛䜙䛾ከయ⌮ㄽ䠄㧗⏣⌜䠅

7䜶䝸䜰䝅䝳䝞䞊䜾⌮ㄽ䛻䛚䛡䜛G0W0 ㏆ఝᐇ⏝ⓗ䛷᭷⏝䛺ỗ㛵ᩘᙧ䛾ᵓ⠏䛻䛿ᆒ୍ᐦᗘ㟁Ꮚ䜺䝇⣔䛿኱ኚ᭷ຠ䠖䛯䛸䛘䜀䚸Vxc(r;[n(r)])䛻䛚䛡䜛LDA䜔GGAྠ䛨⣔䜢౑䛳䛶ᙅ⤖ྜ⣔䛻䛚䛡䜛 Kij 䛾ỗ㛵ᩘᙧ䜢ᵓ⠏䛧䜘䛖䚹
cf. YT, J. Phys. Soc. Jpn. 45, 786 (1978); .49, 1267 (1980).
Åᑐ㛵ᩘ䛾␗᪉ᛶ䜒ධ䛳䛶䛔䜛Å Tc ࢆ୙ኚ࡟ಖࡕ࡞ࡀࡽZኚᩘ࡛✚ศࡍࡿࠋ➨୍ཎ⌮䛛䜙䛾ከయ⌮ㄽ䠄㧗⏣⌜䠅

8ᙅ⤖ྜ㡿ᇦ䛷䛾Kijࡍࡤࡽࡋ࠸ᑐᛂ㛵ಀಀ!

ÅÆÆ
i*: time-reversed orbital of
the KS orbital iᙅ⤖ྜ㡿ᇦࡢ୙ᆒ୍ᐦᗘ⣔࡟࠾ࡅࡿTc Ỵᐃࡢࢫ࣮࣒࢟
➨୍ཎ⌮䛛䜙䛾ከయ⌮ㄽ䠄㧗⏣⌜䠅9ືⓗᑐ┦㛵㛵ᩘ

Qsc(q,Z)ᚑ᮶ࡢ࢔ࣉ࣮ࣟࢳ➨୍ཎ⌮䛛䜙䛾ከయ⌮ㄽ䠄㧗⏣⌜䠅

10

Qsc(q,Z)䛾෌ᐃᘧ໬~ࡇࡢg࡟ࡣ⮬ᕫ࢚ࢿࣝࢠ࣮ࡢ⧞ࡾ㎸ࡳຠᯝ࡜ࣂ࣮ࢸࢵࢡࢫ⿵ṇࡢ୧᪉ࡀྵࡲࢀࡿࠋ➨୍ཎ⌮䛛䜙䛾ከయ⌮ㄽ䠄㧗⏣⌜䠅11ᙉ⤖ྜ㡿ᇦ䛷䛾KijKS㌶㐨ࢆ౑ࡗࡓQscᙅ⤖ྜ㡿ᇦᙉ⤖ྜ㡿ᇦ࡛ࡣVij ࡢ௦ࢃࡾ࡟ ~gij ࢆ౑࠺䟿㸦ὀ㸧ᙉ⤖ྜ㡿ᇦ࡛ࡣࠊ~g ࡢ :౫Ꮡᛶࡣᙅ࠸ࠋ➨୍ཎ⌮䛛䜙䛾ከయ⌮ㄽ䠄㧗⏣⌜䠅12⌧ᐇ≀㉁㐺⏝᫬䛾ᇶᮏᡓ␎㸱ࢫࢸࢵࣉᡓ␎
1. LDA ࡸ GGAィ⟬ࢆཧ⪃࡟ࡋ࡚ࠊ㐺ษ࡞ᚤどⓗࣔࢹࣝࣁ࣑ࣝࢺࢽ࢔ࣥHࢆᵓ⠏ࡍࡿࠋࡇࡢH࡟ࡣࠊ୍㟁Ꮚศᩓ㛵ಀࡸ㟁Ꮚ㟁Ꮚ㟁Ꮚࣇ࢛ࣀࣥ┦஫స⏝ࢆỴࡵࡿᇶᮏᐃᩘࡀྵࡲࢀࡿࠋ
2.ࡇࡢH࡟ᡃࠎࡢTcỴᐃࢫ࣮࣒࢟ࢆ㐺⏝ࡋ࡚ࠊ H࡟ྵࡲࢀࡿᇶᮏᐃᩘࡢ࠺ࡕ࡛㘽࡟࡞ࡿᇶᮏᐃᩘࢆ≉ᐃࡋࠊࡑࡢTcไᚚࡢヲ⣽ࢆ᫂☜࡟ࡍࡿࠋ
3. ᚓࡽࢀࡓ⤖ᯝࢆᐇ㦂್࡜ẚ㍑ࡍࡿ࡜ඹ࡟ࠊ㘽࡟࡞ࡿᇶᮏᐃᩘࢆࢫ࢖࣮ࣉࡋ࡚Tc ࡢኚ໬ᇦࢆㄪ࡭ࠊTc ࡢ᭱኱್ࢆண ࡍࡿࠋ➨୍ཎ⌮䛛䜙䛾ከయ⌮ㄽ䠄㧗⏣⌜䠅13౛䠍: 䜾䝷䝣䜯䜲䝖ᒙ㛫໬ྜ≀KC8: Tc = 0.14K [Hannay et al., PRL14, 225(1965)]
CaC6: Tc = 11.5K [Weller et al., Nature Phys. 1, 39(2005);
Emery et al., PRL95, 087003(2005)]
ຍᅽୗ䛷䛿15.1K䜎䛷ୖ᪼ [Gauzzi et al., PRL98, 067002(2007)]

CaC6

༢࡟KࢆCa࡟ኚ࠼ࡓࡔࡅ࡛ࠊ࡝࠺ࡋ࡚Tc 䛜100ಸ䛻䛺䛳䛯䛛䛸䛔䛖⌮⏤䜢▱䜛䛣䛸䛜᭱㛵ᚰ஦䛷䛒䜛䚹➨୍ཎ⌮䛛䜙䛾ከయ⌮ㄽ䠄㧗⏣⌜䠅14㟁Ꮚᵓ㐀䝞䞁䝗ィ⟬:KC8:
LiC2:CaC6,YbC6:[Ohno et al., JPSJ47, 1125(1979); Wang et al., PRB44, 8294(1991)][Csanyi et al., Nature Phys.1, 42 (2005)][Mazin,PRL95,227001(2005);Calandra & Mauri,PRL95,237002(2005)]

㔜せ䛺ඹ㏻䛾ᛶ㉁1) 䠎ḟඖ㟁Ꮚ⣔䛸䠏ḟඖ㟁Ꮚ⣔䛾ඹᏑ2) Interlayer≧ែ䛾䠏ḟඖ㟁Ꮚ⣔ (䛣䜜䛿䝞䞁䝗㉁㔞䛜m*䛾䠏ḟඖᆒ୍㟁Ꮚ䜺䝇䛷䜘䛟㏆ఝ䛷䛝䜛䠅 䛰䛡䛜㉸ఏᑟ䛻䛺䜛䚹➨୍ཎ⌮䛛䜙䛾ከయ⌮ㄽ䠄㧗⏣⌜䠅

15䜾䝷䝣䜯䜲䝖ᒙ㛫໬ྜ≀䛾ᚤどⓗ䝰䝕䝹ᐇ㝿䛿䛣䛾ᶍᆺ䛿1982ᖺ䛻KC8䛾㉸ఏᑟ䜢ㄝ᫂䛩䜛䛯䜑䛻ᑟධ䛥䜜䛶䛔䛯[YT, JPSJ 51, 63 (1982)] 䚹2009ᖺ䛻඲䛟ྠ䛨ᶍᆺ䛜Tc䛜100ಸ㐪䛖䛻䜒ᣊ䜟䜙䛪CaC6:䛻䜒㐺⏝䛥䜜䜛䛣䛸䜢ぢฟ䛧䛯[YT, JPSJ 78, 013703 (2009)]䚹
➨୍ཎ⌮䛛䜙䛾ከయ⌮ㄽ䠄㧗⏣⌜䠅

16

Tc䛾ィ⟬⤖ᯝKCa㟁Ꮚ౯Z12ᒙ㛫㊥㞳d~ 5.5A~ 4.5A
ศ๭ẚf~ 0.6~ 0.15
䝞䞁䝗㉁㔞m*~ me (s-like) ~ 3me (d-like)cf. ཎᏊ㉁㔞mM䛿Ṥ䛹ྠ䛨䚹➨୍ཎ⌮䛛䜙䛾ከయ⌮ㄽ䠄㧗⏣⌜䠅

17Tc䛾᭱኱್ண

䖂Z 䛸 m*䛾䠎䛴䛜㘽䛻䛺䜛ᇶᮏᐃᩘ䖂Tc 䛾᭱኱್䛿䜎䛰ᩘಸ䛻䛿ฟ᮶䜛䛜䚸Ỵ䛧䛶100䠧䜢㉺䛘䛺䛔䛷䛒䜝䛖䚹➨୍ཎ⌮䛛䜙䛾ከయ⌮ㄽ䠄㧗⏣⌜䠅

18䠞䠟䠯⌮ㄽ䛻䛚䛡䜛[0a0: lattice constant㧗࠸Tc Æ ᚲ↛ⓗ࡟▷࠸[0ᐇ✵㛫䛛䜙䛾䜰䝥䝻䞊䝏䛷[0 䛜䝊䝻䛾ᴟ㝈䛛䜙ᑐ┦஫స⏝䜢ィ⟬䛩䜛᪉ἲ䜢⪃䛘䜘䛖!
➨୍ཎ⌮䛛䜙䛾ከయ⌮ㄽ䠄㧗⏣⌜䠅

19ᑐ┦஫స⏝䛾ホ౯ᇶᮏㄆ㆑㸸ࡶࡋ⣔ࡢࢧ࢖ࢬࡀ[0 ࡼࡾࡶ༑ศ࡟኱ࡁࡅࢀࡤࠊ᭷㝈ࡢNࢧ࢖ࢺ⣔࡛ࡶ㟁Ꮚᑐᙧᡂࡢ≀⌮ࡣᤊ࠼ࡽࢀࡿࡣࡎࠋÆ ࡶࡋ [0 ࡀ▷ࡅࢀࡤࠊNࡣ኱ኚᑠࡉࡃタᐃ࡛ࡁࡿࠋ➨୍ཎ⌮䛛䜙䛾ከయ⌮ㄽ䠄㧗⏣⌜䠅20

౛䠎: 䝣䝷䝺䞁㉸ఏᑟయᇶᮏⓗ࡞≉ᚩ1) C60 ศᏊࢆ༢఩࡜ࡍࡿศᏊᛶ⤖ᬗ2) Tc ࡀ18-38Kࡢ㉸ఏᑟࡀC60 ศᏊࡢ㸱㔜⦰㔜ࡋࡓt1u‽఩࡟⏤᮶ࡍࡿ⊃࠸ఏᑟᖏ࡟༙ศ㟁Ꮚࡀワࡲࡗࡓ࡜ࡁ࡟ฟ⌧ࡍࡿ ࣂࣥࢻᖜ W䡚 0.5eV ࠋ3) 㧗࠸࢚ࢿࣝࢠ࣮ Z0 䡚0.2eV ࢆᣢࡘศᏊෆࣇ࢛ࣀࣥᶵᵓ࡜⪃࠼ࡽࢀ࡚࠸ࡿࠋࡓࡔࡋࠊศᏊෆࢡ࣮ࣟࣥ᩺ຊU ࡶᙉࡃ࡚ࠊࡑࡢ኱ࡁࡉࡣࣇ࢛ࣀࣥ፹௓ᘬຊ -2DZ0࡜ྠ⛬ᗘࠋࡇࡇ࡛ࠊ D ࡣ↓ḟඖ໬ࡉࢀࡓ㟁Ꮚࣇ࢛ࣀࣥ⤖ྜᐃᩘ D䡚2 ࠋÆ U䡚2DZ0~

cf. O. Gunnarsson, Rev. Mod. Phys. 69, 575 (1997).
➨୍ཎ⌮䛛䜙䛾ከయ⌮ㄽ䠄㧗⏣⌜䠅

21䝝䝞䞊䝗䞉䝩䝹䝇䝍䜲䞁䝰䝕䝹ࣂࣥࢻከ㔜ᛶ
ࣔࢵࢺ⤯⦕┦࡜ࡢ➇தࢆ⪃࠼ࡿ࡜ࡁ࡟ࡣ㔜せ [Han, Koch, &Gunnarsson, PRL84, 1276 (2000)]ࡔࡀࠊ㉸ఏᑟ⮬యࢆㄽࡎࡿ
࡜ࡁ࡟ࡣࡑࢀ࡯࡝㔜せ࡛࡞࠸[Cappelluti, Paci, Grimaldi, &Pietronero, PRB72, 054521 (2005)]ࠋ

ࡇࡢ⣔ࢆグ㏙ࡍࡿ᭱ᑠᶍᆺ㸸࡞ࡐ࡞ࡽࠊ[0 ࡣ኱ኚ▷࠸ࠋ(2a0௨ୗ㸧 cf. YT, JPSJ65, 1544, 3134 (1996).
➨୍ཎ⌮䛛䜙䛾ከయ⌮ㄽ䠄㧗⏣⌜䠅22㟁Ꮚ䝗䞊䝥䛾 C60
ࣂࣥࢻィ⟬࡟౫ࢀࡤ

D=2࡛ࡣࠊ㏻ᖖࡢ㟁Ꮚࣇ࢛ࣀࣥ┦஫స⏝ᐃᩘOࡣ⣙0.6࡟࡞ࡿࠋ

ຍᅽୗࡢCs3C60 [Takabayashi et al., Science 323, 1589(2009)] ࡢ⤖ᯝࢆྵࡵࠊ⤖ᬗᵓ㐀ࡢ㐪࠸࡟ࡼࡿࡢ㐪࠸࡛Tc ࡢ㐪࠸ࡶ࠺ࡲࡃ෌⌧ฟ᮶ࡓࠋ➨୍ཎ⌮䛛䜙䛾ከయ⌮ㄽ䠄㧗⏣⌜䠅

23௬᝿ୖ䛾ṇᏍ䝗䞊䝥䛾C60
ṇᏍ䝗䞊䝥䛾C60 : 䠑㔜⦰㔜䛧䛯hu ౯㟁Ꮚᖏ䛻䛚䛡䜛㉸ఏᑟÆ D=3➨୍ཎ⌮䛛䜙䛾ከయ⌮ㄽ䠄㧗⏣⌜䠅24䜘䜚኱䛝䛺D䛾ሙྜ䜒䛧D䛜䠏䜘䜚኱䛝䛟䛺䜛䛸䚸Tc䛿䛹䛖䛺䜛䛛䠛䜘䜚ᑡ䛺䛔ᩘ䠄NS䠅䛾S㟁Ꮚ⣔䛷䛿 D 䛿䜘䜚኱䛝䛟䛺䜛䛸ᮇᚅ䛥䜜䛶䛔䜛䠖 A. Devos & M Lannoo,
PRB58, 8236 (1998).

C36 ࡢሙྜࡀ㠃ⓑ࠸㸸 D=4
C36 ᅛయࡣ᪤࡟ྜᡂࡉࢀ࡚࠸ࡿC. Piskoti,
J. Yarger & A. Zettl, Nature 393, 771 (1998);
M. Cote, J.C. Grossman, M. L. Cohen, & S. G.
Louie, PRL81, 697 (1998).
➨୍ཎ⌮䛛䜙䛾ከయ⌮ㄽ䠄㧗⏣⌜䠅25௬᝿ୖ䛾C36ᅛయ
䜒䛧C36 䛻䛖䜎䛟䝗䞊䝥䛷䛝䛯䜙䚸 D=4䛾⣔䛜ᐇ⌧䛷䛝䜛䚹➨୍ཎ⌮䛛䜙䛾ከయ⌮ㄽ䠄㧗⏣⌜䠅26

䜎䛸䜑
10 SCDFT䛾䜼䝱䝑䝥᪉⛬ᘧ䛻䛚䛡䜛ᑐ┦஫స⏝䛻ᑐ䛩䜛᪂䛧䛔ỗ㛵ᩘᙧ䜢ᥦ᱌䛧䛯䚹
20 ࢢࣛࣇ࢓࢖ࢺᒙ㛫໬ྜ≀࡟㐺⏝ࡋ࡚ᡂຌࡋࡓࠋ
࡞࠾ࠊTc ࡢ᭱኱್ࡣ.ࢆ㉺࠼࡞࠸࡛࠶ࢁ࠺ࠋ
30 ࣇࣛࣞࣥ㉸ఏᑟయ࡟ࡶ㐺⏝ࡋ࡚ࠊࡇࡢ≀㉁⩌࡛ࡣ.ࢆ㉺࠼ࡿTc ࡀᮇᚅ࡛ࡁࡿ࡛࠶ࢁ࠺ࠋ௒ᚋ䛾ㄢ㢟:䛣䛾䝇䜻䞊䝮䛻䜘䜛ィ⟬䛿䜎䛥䛻ጞ䜎䛳䛯䜀䛛䜚䛷䛒䜛䚹䜘䜚ከ䛟䛾⤒㦂䜢㔜䛽䛶䚸ỗ㛵ᩘᙧ䛾ᨵⰋ䜢ᅗ䜚䛴䛴䚸ᐊ ㉸ఏᑟయ䛻䜅䛥䜟䛧䛔≀⌮䛸䛭䜜䜢ᐇ⌧䛩䜛≀㉁⩌䛾㛤Ⓨ䛻㈨䛧䛯䛔䚹➨୍ཎ⌮䛛䜙䛾ከయ⌮ㄽ䠄㧗⏣⌜䠅27