¶q¤lÀNº¸²GÅ鲤¶ ¡V ½Í¤µ¦~ªº¿Õ¨©º¸ª«²z¼ú
®v¤jª«²z¨t ±i©úõ (1999)
¤µ¦~ªº¿Õ¨©º¸ª«²z¼ú¹{µ¹¥v¤¦¦ò¤j¾ÇªºLaughlin¡AôÛ¤ñ¨È¤j¾ÇªºStormer¡A¤Î´¶ ªL´µ´°¤j¾Çªº±Zµa(Daniel Tsui)¡Aªí´¥LÌ ¦b¶q¤lÀNº¸²GÅé¬ã¨s¤Wªº°^Äm¡C²GÅé¬O¤j®a³£«Ü¼ô±xªºªF¦è¡A¦ý¬O¤°»ò¬O¶q¤lÀNº¸²GÅé(quantum Hall liquid)©O? ³oÓ¦Wµü«üªº¬O¹q¤l¦b¤@ºØ«Ü¯S§Oªº±¡ªp¤U§Î¦¨ªº²GÅ骬ºA ¡C³oÓ¯S§Oªºª¬ºA¥² ¶·¦P®Éº¡¨¬¤U¦C´XÓ±ø¥ó: 1. ¹q¤l¥²¶·ÄY®æ«]¦b¤Gºûªº¥±¤W¡C2. ¥²¶·¦³«Ü±jªººÏ³õ(´XÓ Tesla¥H¤W)¡C3. ·Å«×¥²¶·°±o«Ü§C (§C©óµ´¹ï·Å«×¥|«×)¡C¬°¤Fº¡¨¬²Ä¤@Ó±ø¥ó¡A³oÓ¶q¤lÀNº¸²GÅéÁ`¬O³Q¡§¸Ë¡¨¦b¥b¾ÉÅé§÷®Æªº¤¶±ùØ¡C§Q¥Î¤¶±ùئ۵M²£¥Íªº¹q³õ§â¥¦«]¦b¤Gºûªº¥±ùØ¡C¥¦¤£¶È¦û¤F«Ü¤pªº±¿n(¤p©ó´X²@¦Ì¥¤è)¡A¦Ó¥B¥Ñ©ó¥b¾ÉÅé§÷®Æªºªý¹j¡A¨S¿ìªk³Qª½±µ¬Ý¨ì¡C¬JµM¦p¦¹¡A¬°¤°»òª«²z¾Ç®aªº¬ã¨s·|¨«¨ì³oÓ¤û¨¤¦y¨Ó? ³o¤S¬°¤°»ò¬O¤@Ó«nªº¬ã¨s? ¤U±¥ý²³æ¦^ÅU³oÓ¬ã¨sªº¾ú¥v¡C
ÀNº¸®ÄÀ³À³¸Ó¬O¤j®a³£«Ü¼ô±xªº²{¶H¡C ¥¦¬O¦b1879¦~¥Ñ·í®É¤´¦b Johns Hopkins ¤j¾Ç·í¬ã¨s¥ÍªºÀNº¸ (E.H. Hall) ©Òµo²{ªº¡C³oÓ®ÄÀ³³Q¼sªx¹B¥Î¦b´ú¶q¤@Ӽ˫~ùؾɹq²É¤lªº¹q²ü»P±K«×¡C¤C¹s¦~¥N¥½´Á¡A¦b¼w°ê¦³Ó¬ã¨s¤p²Õªº¬ã¨s«ÂI¬O¦b´ú¶q¥b¾ÉÅ餶±ùتº¹q¤l®ðÅ骺ÀNº¸®ÄÀ³¡Cµy¦´X¦~¤é¥»¦³´X¦ìª«²z¾Ç®a´¿°µ¤F¤@¨Ç³o¤è±ªº²z½×pºâ¡A³o¨Çpºâ¸Ì³£²o¯A¨ì«Ü±jªººÏ³õ¡C¼w°êªº¬ã¨s¤p²Õ(¥Ñ von Klitzing±a»â)§Æ±æ¥L̪º´ú¶q¯à©M²z½×¤ñ¸û¡A¥H¤F¸Ñ¥b¾ÉÅ餶±ùتº¹q¤l®ðÅ骺°ò¥»©Ê½è¡C
¦b1979¦~¦~©³¡A¥LÌ«Ü·N¥~ªº µo²{¤F¹q¤l®ðÅé¦b¤Wzªº·¥ºÝ±ø¥ó¤Uªº¦æ¬°©M²z½×¹w´ú¤j¦³¤£¦P¡C·LÆ[ªº²z½×pºâ±o¨ìªº¹qªýÀ³¸Ó©M¥~¥[ ºÏ³õªñ¥G¦¨¥¿¤ñªºÃö«Y¡C¥L̶q¨ìªº¹qªý«o¬O§e¶¥±èª¬¡C¤]´N¬O»¡¡A¦b¡§¥¥x³¡¥÷¡¨¹q¤l®ðÅ骺¹qªý¤£ÀHµÛ¥~¥[ºÏ³õ ¦ÓÅÜ (¨£¹Ï)¡C¤×¦³¬ÆªÌ¡A§Y¨Ï±Ä¥Î¤£¦Pªº¼Ë«~¡A³o¨Ç¡§¥¥x¹qªý¡¨¤´¥H¦Ê¸U¤À¤§¤@¥ª¥kªººë½T«×¸¨¦b (25813.80/ n ) ¼Ú©iªºÈ¤W (Von Klitzing et al, 1980)¡C¹ïÀ³©ó¤£¦Pªº¥¥x¡A³o¸Ìªº n ¥i¥H¬O 1,2,3 µ¥ªº¾ã¼Æ¡C³oºØÅå¤Hªººë½T«×Åã¥Ü¥b¾ÉÅ餶±ùتº¹q¤l®ðÅé¦b·¥§C·Å¥H¤Î·¥±jºÏ³õªº±ø¥ó¤U¦Û¦¨¤@ºØ¿W¥ß©ó©P³ò¥b¾ÉÅé§÷®Æªº¶q¤lºA¡C¨Æ¹ê¤W¡A25813.80 ¼Ú©iªº¥X²{µ´«D°¸µM¡C¥¦¥¿¥©¬O´¶®Ô§J±`¼Æ°£¥H¹q¤l¹q²üªº¥¤è h/e2¡C
Von Klitzingªº¬ã¨sµ²ªG¤½¥¬«á¡A¬ü°êªº¨©º¸¹êÅç«Ç (´X¦~«e§ï¦W¬°Lucent Technology) ªºStormer, Tsui, ¤ÎGossard¸ÕµÛ«½Æ°µ³oÓ¹êÅç¡C¥ḺĥΤF¹q¤l¶Ç¿é¯S©Ê¸û¨Î ªºGaAs/AlGaAs²§½è±µ±¡C¥i¥H¦b·Å«×¤ÎºÏ³õªºn¨D ¸û¤£ÄY®æªº±ø¥ó¤U±o¨ì¤Wzªºµ²ªG¡C¦b³o¦P®É¡A·í®É¦b¨©º¸¹êÅç«Ç¤u§@¡A¦~¶È¤T¤Q¥XÀY¡AµL¬Æ¦W®ðªº Laughlin «ü¥X¤Wzªº¡§¾ã¼Æ¡¨¶q¤l¤ÆÀNº¸ ®ÄÀ³ (integer quantum Hall effect) ¦s¦bªºÃöÁä¦b©ó³oºØ¨t²ÎÁô§tªº¹ïºÙ©Ê (Laughlin, 1981)¡C·§²¤ªº»¡¡A³oºØ¹ïºÙ©Ên¨D¦b¥b¾ÉÅ餶±¤¤¨ü¨ì±jºÏ³õ§@¥Îªº¹q¤l®ð¡A¦b³q¹L¾É¹q¹q¤l«á¡A¹q¤l®ðªºªi¨ç¼Æ¥²¶·¦^´_¨ì³q¹L¹q¤l«eªºª¬ºA¡C³oÓ±ø¥ó°ß¦³·í¹q¤l®ðÅ骺¹qªýºë½Tªº¸¨¦b h/(e2 n) ®É¤~±o¥H«O«ù¡C¦Ón¬O¾ã¼Æ©M³q¹Lªº¹q²ü¼ÆÁ`¬O¾ã¼Æ¦³ª½±µªºÃöÁp¡A©Ò¥H n ¤£¥i¯à¬O«D¾ã¼Æ (¨Ò¦p»¡¡A¤£¥i¥H¬O¤À¼Æ)¡C³oÓ²z½×´£¥X«á¨³§Y¬°¤j¦h¼Æªºª«²z¾Ç®a©Ò±µ¨ü¡C
©Ò¥H¡A·í Stormer µ¥¤H¦b 1982 ¦~Ä~Äò°§C·Å«×¡N¥[¤jºÏ³õ¡A¥X¤H·Nªíªº
°µ¥X n ¬O¤À¼Æªº¹qªý¥¥x®É (
´¡¹Ï»¡©ú
¨ã¦³¶¥±èµ²ºcªºÀNº¸¹qªý (¤W¹Ï)¡C³Ì¤W±ªº¥¥x¹ïÀ³ªº¹qªý¬O 3h/ e2¡A©ÎªÌ¬Oh/( e2/3)¡A§Y©Ò¿×ªº¤À¼ÆÀNº¸¹qªý¡C¤U±ªº¥¥x¹ïÀ³ªº¹qªý¤À§O¬O h/ e2, h/(2 e2) µ¥µ¥¡A§Y©Ò¿×ªº¾ã¼ÆÀNº¸¹qªý¡C¤£¦P¦±½u¬O¦b¤£¦P·Å«×¤U´ú¶qªº¡C
¬°¤F¯àªY½à³oÓ¬ã¨sªº«n©Ê¡A§ÚÌ¥² »Ý§ó²`¤Jªº¨Ó»{ÃѳoÓ²z½×¡C°ò¥»¤W¡A¾ã¼Æ¶q¤l¤ÆÀNº¸®ÄÀ³©M¤À¼Æ¶q¤l¤ÆÀNº¸®ÄÀ³ªº·LÆ[¾÷¨î¨ä¹ê¨Ã¤£¤@¼Ë¡C«eªÌªº¸ÑÄÀ¥i¥H¤£¥Î¤Þ¤J¹q¤l¡X¹q¤l¥æ¤¬§@¥Î¡A«áªÌ«h«D±o¦Ò¼{¹q¤l¡X¹q¤l¥æ¤¬§@¥Î¤£¥i¡C³o¤@ÂIStormer, Tsui, ¸òGossard ¦b¤@¶}©l´N¤w¸g«ü¥X¨Ó¤F¡C³o¤]¬O§Ú̧⥦¥s°µ¡§²GÅ顨ªºì¦]¡C¦]¬°¶q¤l¦hÅé²z½×¸Ì³q±`§â²É¤l¶¡ªº¥æ¤¬§@¥Î«Ü«n(¦Ó¤S¤£¬O©TÅé)ªºÅé¨tºÙ¬°¶q¤l²GÅé¡C
²{¦b¡A§ÚÌ°¨¤W±Á{¤F¤@ӴƤ⪺¶q¤l¦hÅé°ÝÃD¡C
ÁöµM Laughlin, Stormer,
¸òTsuiµ¥¤T¤H¬O¦]¬°¦b¤À¼Æ¶q¤lÀNº¸®ÄÀ³¤Wªº¬ã¨sÀò¼ú¡C¦³
½ìªº¬O¿Õ¨©º¸¼úªºµ¹¼úì¦]¸Ì¨Ã¨S¦³´£¨ì¡§¤À¼Æ¶q¤lÀNº¸®ÄÀ³¡¨³oÓ¦Wµü¡A¦Ó¬O±j½Õ¥L̵o
²{¤F¡§¤@ºØ¦³¤À¼Æ¹q²ü¿EµoºAªº·s«¬¶q¤l²GÅ顨¡C
¶q¤lÀNº¸²GÅ骺ºë·L¤§³B¤ñ°_¶W¾ÉÅé©Î¶W¬yÅé¥i¿×¦³¹L¤§¦ÓµL¤£¤Î
¦b¤E¹s¦~¥Nªì¡Aª«²z¾Ç®a´¶¹M»{¬°Ãö©óÀNº¸²GÅé¸Óµo²{ªº¥þ³Qµo²{¤F
°Ñ¦Ò¤åÄm
G.P. Collins, Fractionally charged quasiparticles signal their presence with noise, Physics Today, November, p.17 (1997).
S. Das Sarma and A. Pinczuk eds., Perspectives in Quantum Hall Effects : Novel Quantum Liquids in Low-Dimensional Semiconductor Structures, John Wiley and Sons (1996).
R.B. Laughlin, Quantized Hall conductivity in two dimensions, Phys. Rev. B 23, 5632 (1981).
R.B. Laughlin, Anomalous quantum Hall effect ¡V an incompressible quantum fluid with fractionally charged excitations, Phys. Rev. Lett. 50, 1395 (1983).
R.F. Prange and S.M. Girvin eds., The Quantum Hall Effect, 2nd ed. New York, Springer-Verlag (1990).
D.C. Tsui, H.L. Stormer, and A.C. Gossard, Two-dimensional magnetotransport in the extreme quantum limit, Phys. Rev. Lett. 48, 1559 (1982).
K. von Klitzing, G. Gorda, and M. Pepper, New method for high-accuracy determination of the fine-structure constant based on quantized Hall resistance, Phys. Rev. Lett. 45, 494 (1980).
¶i¤@¨Bªº¾\Ū
P.W. Anderson, When the electron falls apart, Physics Today, October, p.42 (1997).
B. Davis, Splitting the electron, New Scientist, January, p.36 (1998).
S. Kivelson, D.H. Lee, and S.C. Zhang, Electrons in flatland, Scientific American, March, p.64 (1996).
A.H. MacDonald, Fractional charges in an interacting electron system, Scienc, 17 February, p.977 (1995).